Persistencia setters, compat-resolved, journald→CAS, compat-polkit

- hostnamed: SetHostname llama sethostname(2) + cache. SetStaticHostname
  escribe atómico a /etc/hostname (tmp + fsync + rename, perms 0644).
  Set{Pretty,Icon,Chassis,Deployment,Location} mergean k=v en
  /etc/machine-info preservando otras keys. Validación: hostname RFC 1123
  + chassis enum.
- timedated: SetTimezone valida que /usr/share/zoneinfo/<tz> exista,
  hace symlink atómico a /etc/localtime.
- localed: SetLocale valida formato KEY=value, escribe a /etc/locale.conf.
- compat-resolved (nuevo): org.freedesktop.resolve1.Manager con
  ResolveHostname (vía tokio::lookup_host) y ResolveAddress (getnameinfo).
  ResolveRecord devuelve NotSupported.
- journald-compat: persiste cada datagram al CAS por SHA. Append a
  ~/.local/share/ente/journal/index.log con
  timestamp_ms:source:unit:sha_hex. Mutex serializa escrituras.
- compat-polkit (nuevo): org.freedesktop.PolicyKit1.Authority always-yes.
  CheckAuthorization/CheckAuthorizationByAsync responden true,false,{}.
  EnumerateActions vacío. Loguea action_id + pid/uid del subject.

7 compat-shims operativos en paralelo.

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

crates/ente-polkit-compat/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "ente-polkit-compat"
+version = "0.0.1"
+edition.workspace = true
+license.workspace = true
+publish.workspace = true
+
+[[bin]]
+name = "ente-polkit-compat"
+path = "src/main.rs"
+
+[dependencies]
+ente-card = { path = "../ente-card" }
+ente-bus = { path = "../ente-bus" }
+anyhow = { workspace = true }
+tokio = { workspace = true }
+tracing = { workspace = true }
+tracing-subscriber = { workspace = true }
+zbus = { version = "4", default-features = false, features = ["tokio"] }