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/public/index.html

@@ -1148,13 +1148,26 @@
               </label>
               <span class="form-hint">Enable experimental Agent Teams for all new Claude sessions (disabled by default)</span>
             </div>
+            <div class="form-row">
+              <label>Claude Model</label>
+              <select id="appSettingsClaudeModel" class="form-select">
+                <option value="">Default (CLI setting)</option>
+                <option value="claude-fable-5[1m]">Fable 5 (1M context)</option>
+                <option value="claude-fable-5">Fable 5</option>
+                <option value="opus[1m]">Opus (1M context)</option>
+                <option value="opus">Opus</option>
+                <option value="sonnet">Sonnet</option>
+                <option value="haiku">Haiku</option>
+              </select>
+              <span class="form-hint">Model for new Claude sessions (pinned via the case's .claude/settings.local.json) — takes precedence over the 1M Opus toggle below</span>
+            </div>
             <div class="form-row form-row-switch">
               <label>1M Opus Context</label>
               <label class="switch">
                 <input type="checkbox" id="appSettingsOpusContext1m">
                 <span class="slider"></span>
               </label>
-              <span class="form-hint">Use 1M token context window (model: opus[1m]) for all new sessions</span>
+              <span class="form-hint">Use 1M token context window (model: opus[1m]) for all new sessions — ignored when a Claude Model is selected above</span>
             </div>
             <div class="form-row">
               <label>Thinking Effort</label>
@@ -1203,6 +1216,7 @@
               <label>Default Model</label>
               <select id="appSettingsDefaultModel" class="form-select">
                 <option value="">Default (CLI default)</option>
+                <option value="claude-fable-5">Fable 5 (Most powerful)</option>
                 <option value="opus">Opus (Most capable)</option>
                 <option value="sonnet">Sonnet (Balanced)</option>
                 <option value="haiku">Haiku (Fast & cheap)</option>
@@ -1226,6 +1240,7 @@
                 <option value="haiku">Haiku</option>
                 <option value="sonnet">Sonnet</option>
                 <option value="opus">Opus</option>
+                <option value="claude-fable-5">Fable 5</option>
               </select>
               <span class="form-hint">Quick searches, codebase exploration</span>
             </div>
@@ -1236,6 +1251,7 @@
                 <option value="haiku">Haiku</option>
                 <option value="sonnet">Sonnet</option>
                 <option value="opus">Opus</option>
+                <option value="claude-fable-5">Fable 5</option>
               </select>
               <span class="form-hint">Code writing, feature implementation</span>
             </div>
@@ -1246,6 +1262,7 @@
                 <option value="haiku">Haiku</option>
                 <option value="sonnet">Sonnet</option>
                 <option value="opus">Opus</option>
+                <option value="claude-fable-5">Fable 5</option>
               </select>
               <span class="form-hint">Writing and running tests</span>
             </div>
@@ -1256,6 +1273,7 @@
                 <option value="haiku">Haiku</option>
                 <option value="sonnet">Sonnet</option>
                 <option value="opus">Opus</option>
+                <option value="claude-fable-5">Fable 5</option>
               </select>
               <span class="form-hint">Code review, quality checks</span>
             </div>

src/web/public/session-ui.js

@@ -354,8 +354,10 @@ Object.assign(CodemanApp.prototype, {
       const envOverrides = this.buildEnvOverrides(caseSettings, globalSettings);
       const hasEnvOverrides = Object.keys(envOverrides).length > 0;
       const effort = this.getEffortSetting(globalSettings);
+      // Explicit Claude Model choice (App Settings) wins over the legacy 1M Opus
+      // toggles; both flow as `modelOverride` → the case's .claude/settings.local.json
       const useOpus1m = caseSettings.opusContext1m || globalSettings.opusContext1mEnabled;
-      const modelOverride = useOpus1m ? 'opus[1m]' : '';
+      const modelOverride = globalSettings.claudeModel || (useOpus1m ? 'opus[1m]' : '');
 
       // Step 1: Create all sessions in parallel
       this.terminal.writeln(`\x1b[90m Creating ${tabCount} session(s)...\x1b[0m`);

src/web/public/settings-ui.js

@@ -345,6 +345,7 @@ Object.assign(CodemanApp.prototype, {
       settings.codexDangerouslyBypassApprovals ?? false;
     // Claude Permissions settings
     document.getElementById('appSettingsAgentTeams').checked = settings.agentTeamsEnabled ?? false;
+    document.getElementById('appSettingsClaudeModel').value = settings.claudeModel ?? '';
     document.getElementById('appSettingsOpusContext1m').checked = settings.opusContext1mEnabled ?? false;
     document.getElementById('appSettingsThinkingEffort').value = settings.thinkingEffort ?? '';
     // CPU Priority settings
@@ -1349,6 +1350,7 @@ Object.assign(CodemanApp.prototype, {
       codexDangerouslyBypassApprovals: document.getElementById('appSettingsCodexDangerouslyBypassApprovals').checked,
       // Claude Permissions settings
       agentTeamsEnabled: document.getElementById('appSettingsAgentTeams').checked,
+      claudeModel: document.getElementById('appSettingsClaudeModel').value,
       opusContext1mEnabled: document.getElementById('appSettingsOpusContext1m').checked,
       thinkingEffort: document.getElementById('appSettingsThinkingEffort').value,
       // CPU Priority settings

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