own /effort: respawn-with-resume carrying --effort, picker UX (T-412)

Spike result (probed claude 2.1.175 over stream-json): there is NO
set_effort/set_thinking_effort control subtype — both are rejected. The
lever is the `--effort <level>` spawn flag (low/medium/high/xhigh/max;
settings.json effortLevel is the persisted default). So changing effort
restarts the process: respawn-with-resume keeps the conversation and
carries the flag — the same continuity /clear and /resume already rely on.

- SpawnSpec.effort → orchestrator appends `--effort <level>`.
- claude_pane: /effort <level> validates and respawns (toast explains the
  restart); bare /effort opens a picker; the pane re-applies its effort on
  every later respawn. Invalid level → local notice listing levels.
- ModelPickerCard generalised minimally (title + isCurrent predicate) so
  the effort picker reuses it; effort needs exact matching because `high`
  is a substring of `xhigh` and alias-containment would mis-mark it.
- SessionStatus.effort + StreamJsonSession.noteEffort: the wire never
  reports effort, so the spawner records what it set; status/sidebar read
  it from the normal status stream.
- Routing: effort moves from the TUI-only catalog to kClideOwnedCommands.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/builtin/claude/src/transcript_reader.dart

@@ -433,7 +433,7 @@ class TranscriptReader {
 /// (T-145, T-168). All fields nullable — a chunk only carries what it saw,
 /// and the reader [merge]s deltas into a running status.
 class SessionStatus {
-  const SessionStatus({this.model, this.permissionMode, this.contextTokens, this.cost, this.contextWindow, this.rateLimitInfo});
+  const SessionStatus({this.model, this.permissionMode, this.contextTokens, this.cost, this.contextWindow, this.rateLimitInfo, this.effort});
 
   /// Assistant `message.model`, e.g. `claude-opus-4-7`.
   final String? model;
@@ -458,7 +458,13 @@ class SessionStatus {
   /// `"rate limited — resets 14:32"` (T-168). Null when not rate-limited.
   final String? rateLimitInfo;
 
-  bool get isEmpty => model == null && permissionMode == null && contextTokens == null && cost == null && contextWindow == null && rateLimitInfo == null;
+  /// The session's effort level (`--effort`, T-412). The wire never reports
+  /// it — clide records what it spawned with via [StreamJsonSession.noteEffort];
+  /// null means the CLI default (settings.json `effortLevel`).
+  final String? effort;
+
+  bool get isEmpty =>
+      model == null && permissionMode == null && contextTokens == null && cost == null && contextWindow == null && rateLimitInfo == null && effort == null;
 
   /// Overlay [other]'s non-null fields onto this one.
   SessionStatus merge(SessionStatus other) => SessionStatus(
@@ -468,6 +474,7 @@ class SessionStatus {
     cost: other.cost ?? cost,
     contextWindow: other.contextWindow ?? contextWindow,
     rateLimitInfo: other.rateLimitInfo ?? rateLimitInfo,
+    effort: other.effort ?? effort,
   );
 
   @override
@@ -478,10 +485,11 @@ class SessionStatus {
       other.contextTokens == contextTokens &&
       other.cost == cost &&
       other.contextWindow == contextWindow &&
-      other.rateLimitInfo == rateLimitInfo;
+      other.rateLimitInfo == rateLimitInfo &&
+      other.effort == effort;
 
   @override
-  int get hashCode => Object.hash(model, permissionMode, contextTokens, cost, contextWindow, rateLimitInfo);
+  int get hashCode => Object.hash(model, permissionMode, contextTokens, cost, contextWindow, rateLimitInfo, effort);
 }
 
 /// Result of [parseTranscriptChunk]: items, version-drift warnings, and