chore: trim verbose docstrings on Portal timeout constants and enum

Cleanup pass after Portal resilience commits (6ccb225, 68a6eec).

Trimmed docstrings that restated information already obvious from the
type/variant names or duplicated elsewhere:

- PORTAL_SERVICE_TIMEOUT: 6 lines -> 3 lines (keep 'why 5s' rationale)
- PORTAL_USER_DIALOG_TIMEOUT: 6 lines -> 2 lines (keep 'why 30s' rationale)
- PortalPhaseTimeout enum: 5 lines -> 1 line (variants are self-documenting)
- Service variant: 2 lines -> 1 line
- TokenDependent variant: 2 lines -> 1 line

Net: -15 lines of comment overhead. No behavior change.

Tests:
- cargo build --release: 0 new warnings (19 baseline preserved)
- cargo test: 97 lib + 3 integration, 0 failed

src/cap_portal.rs

@@ -23,36 +23,21 @@ use tokio::runtime::Runtime;
 
 use crate::args::Args;
 
-/// Timeout for Portal phases that do not require user interaction.
-/// Applies to: Screencast proxy creation, session creation, source selection
-/// (when a restore token is used), session start (token path), and PipeWire
-/// remote fd acquisition.
-///
-/// 5 seconds is generous for healthy xdg-desktop-portal (typically <500ms)
-/// but bounded enough that a stuck service fails fast.
+/// Portal phase timeout when no user interaction is expected (proxy/session
+/// creation, token-path select/start, PipeWire fd). 5s is generous for
+/// healthy xdg-desktop-portal (<500ms typical) but bounded for fast failure.
 const PORTAL_SERVICE_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(5);
 
-/// Timeout for Portal phases that may require a user to click "Allow" in a
-/// desktop dialog. Applies to: source selection and session start when NO
-/// restore token is available (fresh authorization).
-///
-/// 30 seconds gives the user time to find and click the dialog without
-/// causing a spurious timeout failure.
+/// Portal phase timeout when user must click "Allow" in desktop dialog
+/// (select/start without restore token). 30s gives time to find the dialog.
 const PORTAL_USER_DIALOG_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(30);
 
 /// Classification of Portal phase timeouts to drive retry behavior.
-///
-/// `TokenDependent` failures are eligible for a single automatic retry that
-/// clears the cached restore token and re-runs the entire Portal setup with
-/// fresh authorization. `Service` failures are not retried automatically
-/// (the user should restart the Portal service instead).
 #[derive(Debug)]
 enum PortalPhaseTimeout {
-    /// Portal service unresponsive in a phase not related to restore token.
-    /// No automatic retry; user should restart Portal service.
+    /// Portal service unresponsive; not retried (user should restart service).
     Service,
-    /// Portal timed out in a token-dependent phase. Retry eligible: clear
-    /// cached token and try once more with fresh authorization.
+    /// Timed out in token-dependent phase; retried once after clearing token.
     TokenDependent,
 }