feat: proper confirmation-resume flow + per-user tool policy

Fixes the broken confirmation gate where users had no way to approve
or deny a blocked tool call in the web UI.

Changes:
- orchestrator_engine.py: add OrchestrateCheckpoint dataclass, extract
  loop into _run_from_contents(), add resume() function
- openai_orchestrator.py: same treatment — _run_from_messages(), resume()
- routers/orchestrator.py: POST /{job_id}/confirm and /deny endpoints,
  separate _checkpoints store, _resume_job() + _finalize_job() helpers,
  "awaiting_confirmation" job status with pending_confirmation payload
- auth_utils.py: get_tool_policy() and save_tool_policy() helpers reading
  home/{user}/tool_policy.json (allow/deny lists)
- routers/orchestrator.py: loads tool_policy per user and passes
  confirm_allow/confirm_deny to both engines
- app.js: poll loop handles awaiting_confirmation — shows Confirm/Deny
  buttons inline, resumes polling after user action
- settings.html + settings.py: Tool Permissions section with allow/deny
  textareas, POST /settings/tool-policy route
- style.css: .confirm-gate, .confirm-btn, .deny-btn styles

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/static/settings.html

@@ -393,6 +393,35 @@
       </form>
     </div>
 
+    <!-- Tool Permissions -->
+    <div class="section">
+      <h2>Tool Permissions</h2>
+      <p style="font-size:0.8rem; color:var(--pg-muted); margin-bottom:0.5rem; line-height:1.55;">
+        Override the default confirmation gate for orchestrator tools.
+        <strong>Allow list</strong> — tools that run without asking for confirmation.
+        <strong>Deny list</strong> — tools that are always blocked for your account.
+        One tool name per line.
+      </p>
+      <p style="font-size:0.78rem; color:var(--pg-muted); margin-bottom:0.85rem;">
+        Tools requiring confirmation by default: <code>{{ confirm_required_tools }}</code>
+      </p>
+      <form method="POST" action="/settings/tool-policy">
+        <div class="form-group">
+          <label for="allow_list">Allow list (bypass confirmation)</label>
+          <textarea id="allow_list" name="allow_list" rows="3"
+                    placeholder="reminders_clear&#10;cron_remove"
+                    autocomplete="off" spellcheck="false">{{ tool_allow }}</textarea>
+        </div>
+        <div class="form-group">
+          <label for="deny_list">Deny list (always block)</label>
+          <textarea id="deny_list" name="deny_list" rows="3"
+                    placeholder="shell_exec&#10;file_write"
+                    autocomplete="off" spellcheck="false">{{ tool_deny }}</textarea>
+        </div>
+        <button type="submit">Save tool permissions</button>
+      </form>
+    </div>
+
     <!-- Browser cache -->
     <div class="section">
       <h2>Browser Cache</h2>