feat(doctor): Add session-hooks check for settings.json consistency

Adds a new doctor check that verifies all settings.json files in the
town use session-start.sh wrapper for SessionStart and PreCompact hooks.

Without this wrapper, session_id passthrough fails, which breaks
gt seance discovery of sessions.

The check:
- Scans all settings.json files across town, rigs, crew, and polecats
- Warns if any file uses bare 'gt prime' without session-start.sh
- Provides fix hint pointing to the correct wrapper configuration

(gt-77fhi)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/cmd/doctor.go

@@ -58,6 +58,9 @@ Rig checks (with --rig flag):
 Routing checks (fixable):
   - routes-config            Check beads routing configuration
 
+Session hook checks:
+  - session-hooks            Check settings.json use session-start.sh
+
 Patrol checks:
   - patrol-molecules-exist   Verify patrol molecules exist
   - patrol-hooks-wired       Verify daemon triggers patrols
@@ -128,6 +131,7 @@ func runDoctor(cmd *cobra.Command, args []string) error {
 
 	// Config architecture checks
 	d.Register(doctor.NewSettingsCheck())
+	d.Register(doctor.NewSessionHookCheck())
 	d.Register(doctor.NewRuntimeGitignoreCheck())
 	d.Register(doctor.NewLegacyGastownCheck())