feat(settings): Claude Model picker for new sessions; Fable 5 in model dropdowns

App Settings → Claude CLI gains a Claude Model select (claudeModel setting)
that pins the model for new Claude sessions via the case's
.claude/settings.local.json, taking precedence over the 1M Opus toggle.
Fable 5 added to the orchestrator default/phase model dropdowns.

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

src/web/schemas.ts

@@ -305,6 +305,8 @@ export const SettingsUpdateSchema = z
     tunnelEnabled: z.boolean().optional(),
     tabTwoRows: z.boolean().optional(),
     agentTeamsEnabled: z.boolean().optional(),
+    /** Model for new Claude sessions (e.g. "claude-fable-5[1m]", "opus[1m]"); takes precedence over opusContext1mEnabled */
+    claudeModel: z.string().max(50).optional(),
     opusContext1mEnabled: z.boolean().optional(),
     thinkingEffort: z.string().max(20).optional(),
     // UI visibility