feat(yahweh-widget-app-header): promover header standard de explorers

Iter 16. Patrón con 4 consumers idénticos: nakui-explorer,
nouser-explorer, minga-explorer, brahman-broker-explorer todos
declaraban un header flex_row + flex_grow(label) + theme_switcher
+ bg(panel) + border-bottom + text_size(14) + padding(16/12).
Ahora es 1 línea.

crates/modules/ui_engine/widgets/app-header/:
- pub fn app_header(cx, label: impl Into<SharedString>) -> impl IntoElement.
- pub fn app_header_with(cx, label_child: impl IntoElement) — variante
  para left side no-text.
- 3 tests #[gpui::test].

Migración 4 consumers:
- Cada uno: bloque de ~13 líneas → 1 línea app_header(cx, text).
- Borra dep yahweh-widget-theme-switcher (incluida vía app-header).
- Reemplaza import.

Ahorro ~50 líneas UI hardcoded. Cambios visuales del header (padding,
border, text_size) en un solo lugar.

Decisión: sidebar header del MetaApp NO se migra — es de sidebar,
no de app top, styling distinto. Diferente patrón → diferente widget.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -6,6 +6,47 @@ ratio/diff ver `git show <sha>`.
 
 ## 2026-05-10
 
+### feat(yahweh-widget-app-header): promover el header standard de explorers
+Iter 16. Patrón con 4 consumers idénticos: `nakui-explorer`,
+`nouser-explorer`, `minga-explorer`, `brahman-broker-explorer`
+todos declaraban un header `flex_row + flex_grow(label) +
+theme_switcher + bg(panel) + border-bottom + text_size(14) +
+padding(16/12)`. Ahora es 1 línea.
+
+Crate nuevo `crates/modules/ui_engine/widgets/app-header/`
+(`yahweh-widget-app-header`):
+- **Deps**: `gpui`, `yahweh-theme`, `yahweh-widget-theme-switcher`.
+  El switcher se incluye automáticamente.
+- **`pub fn app_header(cx: &mut App, label: impl Into<SharedString>)
+  -> impl IntoElement`**: caso simple con texto plano.
+- **`pub fn app_header_with(cx, label_child: impl IntoElement)`**:
+  variante para cuando el lado izquierdo no es texto plano (icon
+  + text, múltiples spans, etc.).
+- 3 tests `#[gpui::test]`: smoke con string label, con custom
+  child IntoElement, type-check de label con literal/owned/format!.
+
+Migración de los 4 consumers:
+- Cada uno reemplaza un bloque `let header = div().flex().flex_row()...
+  .child(theme_switcher(cx))` (~13 líneas) por
+  `let header = app_header(cx, header_text)` (~1 línea).
+- Cada uno borra dep `yahweh-widget-theme-switcher` (ya no la
+  necesita directo — el `app_header` la incluye internamente).
+- Cada uno reemplaza `use yahweh_widget_theme_switcher::theme_switcher`
+  por `use yahweh_widget_app_header::app_header`.
+
+Total ahorro: ~50 líneas de código UI hardcoded en consumers.
+Cambios visuales en el header (padding, border, text_size) ahora
+viven en un solo lugar.
+
+Tests stack: 3 nuevos en app-header; suites de los 4 consumers
+intactas. Todo verde.
+
+Decisión: el sidebar header del `MetaApp` (que también incluye
+theme_switcher) NO se migra — es un header de sidebar, no de app
+top, y tiene styling distinto (px(12/10/13), sin bg/border-bottom
+porque ya está dentro del panel). Diferente patrón → diferente
+widget si emerge segundo consumer.
+
 ### feat(yahweh-widget-stat-card): promover el patrón stat card como widget
 Iter 15. El patrón "tarjeta de dashboard con border-l accent +
 label + valor grande + descripción + listing opcional" tenía 2

Cargo.lock

@@ -1243,9 +1243,9 @@ dependencies = [
  "brahman-sidecar",
  "gpui",
  "yahweh-theme",
+ "yahweh-widget-app-header",
  "yahweh-widget-banner",
  "yahweh-widget-stat-card",
- "yahweh-widget-theme-switcher",
 ]
 
 [[package]]
@@ -6216,9 +6216,9 @@ dependencies = [
  "gpui",
  "minga-store",
  "yahweh-theme",
+ "yahweh-widget-app-header",
  "yahweh-widget-banner",
  "yahweh-widget-stat-card",
- "yahweh-widget-theme-switcher",
 ]
 
 [[package]]
@@ -6486,9 +6486,9 @@ dependencies = [
  "uuid",
  "yahweh-meta-runtime",
  "yahweh-theme",
+ "yahweh-widget-app-header",
  "yahweh-widget-banner",
  "yahweh-widget-card",
- "yahweh-widget-theme-switcher",
 ]
 
 [[package]]
@@ -6883,9 +6883,9 @@ dependencies = [
  "gpui",
  "nouser-card",
  "yahweh-theme",
+ "yahweh-widget-app-header",
  "yahweh-widget-banner",
  "yahweh-widget-card",
- "yahweh-widget-theme-switcher",
 ]
 
 [[package]]
@@ -13031,6 +13031,15 @@ dependencies = [
  "gpui",
 ]
 
+[[package]]
+name = "yahweh-widget-app-header"
+version = "0.1.0"
+dependencies = [
+ "gpui",
+ "yahweh-theme",
+ "yahweh-widget-theme-switcher",
+]
+
 [[package]]
 name = "yahweh-widget-banner"
 version = "0.1.0"

Cargo.toml

@@ -66,6 +66,7 @@ members = [
     "crates/modules/ui_engine/widgets/banner",
     "crates/modules/ui_engine/widgets/card",
     "crates/modules/ui_engine/widgets/stat-card",
+    "crates/modules/ui_engine/widgets/app-header",
     "crates/modules/ui_engine/widgets/theme-switcher",
 
     # ============================================================

crates/apps/brahman-broker-explorer/Cargo.toml

@@ -11,7 +11,7 @@ brahman-sidecar = { path = "../../shared/brahman-sidecar" }
 yahweh-theme = { path = "../../modules/ui_engine/libs/theme" }
 yahweh-widget-banner = { path = "../../modules/ui_engine/widgets/banner" }
 yahweh-widget-stat-card = { path = "../../modules/ui_engine/widgets/stat-card" }
-yahweh-widget-theme-switcher = { path = "../../modules/ui_engine/widgets/theme-switcher" }
+yahweh-widget-app-header = { path = "../../modules/ui_engine/widgets/app-header" }
 gpui = { workspace = true }
 
 [[bin]]

crates/apps/brahman-broker-explorer/src/main.rs

@@ -35,7 +35,7 @@ use gpui::{
 use yahweh_theme::Theme;
 use yahweh_widget_banner::{banner_themed, Banner};
 use yahweh_widget_stat_card::stat_card;
-use yahweh_widget_theme_switcher::theme_switcher;
+use yahweh_widget_app_header::app_header;
 
 const POLL_INTERVAL: Duration = Duration::from_secs(5);
 const PROBE_TIMEOUT: Duration = Duration::from_secs(1);
@@ -170,19 +170,8 @@ impl Render for Explorer {
             self.last_probe_ms,
         );
 
-        let header = div()
+        // Header standard via widget compartido.
-            .flex()
+        let header = app_header(cx, header_text);
-            .flex_row()
-            .items_center()
-            .px(px(16.))
-            .py(px(12.))
-            .bg(theme.bg_panel.clone())
-            .border_b_1()
-            .border_color(theme.border)
-            .text_color(text)
-            .text_size(px(14.))
-            .child(div().flex_grow().child(header_text))
-            .child(theme_switcher(cx));
 
         // Banner permanente debajo del header con el estado actual.
         // Severidad acorde al kind.

crates/apps/minga-explorer/Cargo.toml

@@ -10,7 +10,7 @@ minga-store = { path = "../../modules/semantic_dht/minga-store" }
 yahweh-theme = { path = "../../modules/ui_engine/libs/theme" }
 yahweh-widget-banner = { path = "../../modules/ui_engine/widgets/banner" }
 yahweh-widget-stat-card = { path = "../../modules/ui_engine/widgets/stat-card" }
-yahweh-widget-theme-switcher = { path = "../../modules/ui_engine/widgets/theme-switcher" }
+yahweh-widget-app-header = { path = "../../modules/ui_engine/widgets/app-header" }
 gpui = { workspace = true }
 
 [[bin]]

crates/apps/minga-explorer/src/main.rs

@@ -34,7 +34,7 @@ use minga_store::PersistentRepo;
 use yahweh_theme::Theme;
 use yahweh_widget_banner::{banner_themed, Banner};
 use yahweh_widget_stat_card::stat_card;
-use yahweh_widget_theme_switcher::theme_switcher;
+use yahweh_widget_app_header::app_header;
 
 const REFRESH_INTERVAL: Duration = Duration::from_secs(2);
 const REPO_DIRNAME: &str = "repo";
@@ -224,19 +224,8 @@ impl Render for Explorer {
             None => format!("Buscando repo en {}…", self.repo_path.display()),
         };
 
-        let header = div()
+        // Header standard via widget compartido.
-            .flex()
+        let header = app_header(cx, header_text);
-            .flex_row()
-            .items_center()
-            .px(px(16.))
-            .py(px(12.))
-            .bg(theme.bg_panel.clone())
-            .border_b_1()
-            .border_color(theme.border)
-            .text_color(text)
-            .text_size(px(14.))
-            .child(div().flex_grow().child(header_text))
-            .child(theme_switcher(cx));
 
         let error_banner = self.error.as_ref().map(|e| {
             banner_themed(cx, Banner::Error, e.clone())

crates/apps/nakui-explorer/Cargo.toml

@@ -11,7 +11,7 @@ yahweh-meta-runtime = { path = "../../modules/ui_engine/libs/meta-runtime" }
 yahweh-widget-banner = { path = "../../modules/ui_engine/widgets/banner" }
 yahweh-widget-card = { path = "../../modules/ui_engine/widgets/card" }
 yahweh-theme = { path = "../../modules/ui_engine/libs/theme" }
-yahweh-widget-theme-switcher = { path = "../../modules/ui_engine/widgets/theme-switcher" }
+yahweh-widget-app-header = { path = "../../modules/ui_engine/widgets/app-header" }
 gpui = { workspace = true }
 serde_json = { workspace = true }
 uuid = { workspace = true, features = ["serde"] }

crates/apps/nakui-explorer/src/main.rs

@@ -33,8 +33,8 @@ use nakui_core::event_log::{EventLog, LogEntry};
 use yahweh_meta_runtime::{preview_value, short_hash, short_uuid};
 use yahweh_theme::Theme;
 use yahweh_widget_banner::{banner_themed, Banner};
+use yahweh_widget_app_header::app_header;
 use yahweh_widget_card::card_themed;
-use yahweh_widget_theme_switcher::theme_switcher;
 
 const REFRESH_INTERVAL: Duration = Duration::from_secs(2);
 
@@ -168,22 +168,10 @@ impl Render for Explorer {
             self.last_load_ms,
         );
 
-        // Header con título a la izquierda + theme switcher a la
+        // Header standard via widget compartido yahweh-widget-app-header
-        // derecha. flex_row + flex_grow del label empuja el switcher
+        // (label flex_grow + theme switcher derecha + bg panel + border
-        // al borde.
+        // bottom + text styling consistente).
-        let header = div()
+        let header = app_header(cx, header_text);
-            .flex()
-            .flex_row()
-            .items_center()
-            .px(px(16.))
-            .py(px(12.))
-            .bg(theme.bg_panel.clone())
-            .border_b_1()
-            .border_color(theme.border)
-            .text_color(text)
-            .text_size(px(14.))
-            .child(div().flex_grow().child(header_text))
-            .child(theme_switcher(cx));
 
         let breakdown_line = if top_breakdown.is_empty() {
             String::new()

crates/apps/nouser-explorer/Cargo.toml

@@ -12,7 +12,7 @@ nouser-card = { path = "../../modules/nouser/card" }
 yahweh-theme = { path = "../../modules/ui_engine/libs/theme" }
 yahweh-widget-banner = { path = "../../modules/ui_engine/widgets/banner" }
 yahweh-widget-card = { path = "../../modules/ui_engine/widgets/card" }
-yahweh-widget-theme-switcher = { path = "../../modules/ui_engine/widgets/theme-switcher" }
+yahweh-widget-app-header = { path = "../../modules/ui_engine/widgets/app-header" }
 gpui = { workspace = true }
 
 [[bin]]

crates/apps/nouser-explorer/src/main.rs

@@ -32,7 +32,7 @@ use nouser_card::Lens;
 use yahweh_theme::Theme;
 use yahweh_widget_banner::{banner_themed, Banner};
 use yahweh_widget_card::card_themed;
-use yahweh_widget_theme_switcher::theme_switcher;
+use yahweh_widget_app_header::app_header;
 
 const REFRESH_INTERVAL: Duration = Duration::from_secs(2);
 const DISCOVERY_TIMEOUT: Duration = Duration::from_secs(3);
@@ -226,21 +226,8 @@ impl Render for Explorer {
             _ => "Buscando daemon nouser vía brahman-broker…".to_string(),
         };
 
-        // Header con título a la izquierda + theme switcher a la
+        // Header standard via widget compartido.
-        // derecha (mismo pattern que nakui-explorer).
+        let header = app_header(cx, header_text);
-        let header = div()
-            .flex()
-            .flex_row()
-            .items_center()
-            .px(px(16.))
-            .py(px(12.))
-            .bg(theme.bg_panel.clone())
-            .border_b_1()
-            .border_color(theme.border)
-            .text_color(text)
-            .text_size(px(14.))
-            .child(div().flex_grow().child(header_text))
-            .child(theme_switcher(cx));
 
         let error_banner = self.error.as_ref().map(|e| {
             banner_themed(cx, Banner::Error, e.clone())

crates/modules/ui_engine/widgets/app-header/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "yahweh-widget-app-header"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+description = "Yahweh — widget app-header: tira superior con label flex_grow + theme switcher a la derecha + bg panel + border bottom. Patrón compartido por las apps explorer del repo."
+
+[dependencies]
+gpui = { workspace = true }
+yahweh-theme = { path = "../../libs/theme" }
+yahweh-widget-theme-switcher = { path = "../theme-switcher" }
+
+[dev-dependencies]
+gpui = { workspace = true, features = ["test-support"] }

crates/modules/ui_engine/widgets/app-header/src/lib.rs

@@ -0,0 +1,96 @@
+//! `yahweh-widget-app-header` — tira superior estándar de las apps
+//! del repo.
+//!
+//! Compone:
+//! - Label dinámico a la izquierda (flex_grow).
+//! - [`theme_switcher`] a la derecha.
+//! - bg = `theme.bg_panel`, text = `theme.fg_text`,
+//!   border-bottom = `theme.border`.
+//! - Padding 16/12, text_size 14.
+//!
+//! Patrón emergente: `nakui-explorer`, `nouser-explorer`,
+//! `minga-explorer`, `brahman-broker-explorer` declaran headers
+//! idénticos sólo cambiando el label. Ahora es 1 línea.
+//!
+//! # Ejemplo
+//!
+//! ```ignore
+//! use yahweh_widget_app_header::app_header;
+//!
+//! let header = app_header(cx, format!("Log: {}  ·  {} entries", path, n));
+//! div().child(header).child(body)
+//! ```
+
+#![forbid(unsafe_code)]
+
+use gpui::{div, prelude::*, px, App, IntoElement, SharedString};
+use yahweh_theme::Theme;
+use yahweh_widget_theme_switcher::theme_switcher;
+
+/// Construye el header standard. Lee `Theme::global(cx)` para los
+/// colors; falla si no hay theme instalado (panic propagado de
+/// `Theme::global`).
+///
+/// `label` es texto plano. Para labels más ricos (ej. icon + text,
+/// múltiples spans), usar [`app_header_with`] que acepta
+/// cualquier child element.
+pub fn app_header(cx: &mut App, label: impl Into<SharedString>) -> impl IntoElement {
+    let label: SharedString = label.into();
+    app_header_with(cx, div().child(label))
+}
+
+/// Variante de [`app_header`] que acepta cualquier `IntoElement`
+/// como contenido del lado izquierdo. El widget envuelve el child
+/// en un `div().flex_grow()` para que el switcher quede pegado a
+/// la derecha.
+pub fn app_header_with(cx: &mut App, label_child: impl IntoElement) -> impl IntoElement {
+    let theme = Theme::global(cx).clone();
+    div()
+        .flex()
+        .flex_row()
+        .items_center()
+        .px(px(16.))
+        .py(px(12.))
+        .bg(theme.bg_panel.clone())
+        .border_b_1()
+        .border_color(theme.border)
+        .text_color(theme.fg_text)
+        .text_size(px(14.))
+        .child(div().flex_grow().child(label_child))
+        .child(theme_switcher(cx))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use gpui::TestAppContext;
+
+    #[gpui::test]
+    fn app_header_constructs_with_string_label(cx: &mut TestAppContext) {
+        cx.update(|cx| {
+            Theme::install_default(cx);
+            let _h = app_header(cx, "Test header");
+        });
+    }
+
+    #[gpui::test]
+    fn app_header_with_accepts_arbitrary_child(cx: &mut TestAppContext) {
+        cx.update(|cx| {
+            Theme::install_default(cx);
+            let _h = app_header_with(
+                cx,
+                div().child(SharedString::from("Custom child")),
+            );
+        });
+    }
+
+    #[gpui::test]
+    fn app_header_label_accepts_owned_or_borrowed(cx: &mut TestAppContext) {
+        cx.update(|cx| {
+            Theme::install_default(cx);
+            let _ = app_header(cx, "literal");
+            let _ = app_header(cx, "owned".to_string());
+            let _ = app_header(cx, format!("formatted {}", 42));
+        });
+    }
+}