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/app.js

@@ -1192,6 +1192,37 @@
                             : '⚡ working…';
                         continue;
                     }
+
+                    if (job.status === 'awaiting_confirmation') {
+                        const pc = job.pending_confirmation || {};
+                        const toolNames = (pc.tools || []).map(t => t.name).join(', ');
+                        thinkingDiv.className = 'message assistant';
+                        thinkingDiv.innerHTML = `<div class="confirm-gate">
+                            <p>${escapeHtml(pc.message || 'Confirm this action?')}</p>
+                            <p class="confirm-tools">Tool${(pc.tools||[]).length !== 1 ? 's' : ''}: <code>${escapeHtml(toolNames)}</code></p>
+                            <div class="confirm-actions">
+                                <button class="confirm-btn">Confirm</button>
+                                <button class="deny-btn">Deny</button>
+                            </div>
+                        </div>`;
+
+                        const confirmed = await new Promise(resolve => {
+                            thinkingDiv.querySelector('.confirm-btn').onclick = () => resolve(true);
+                            thinkingDiv.querySelector('.deny-btn').onclick  = () => resolve(false);
+                        });
+
+                        thinkingDiv.className = 'message assistant thinking';
+                        thinkingDiv.textContent = confirmed ? '⚡ confirmed — continuing…' : '⚡ denied — finishing…';
+
+                        const action = confirmed ? 'confirm' : 'deny';
+                        const resumeRes = await fetch(`/orchestrate/${job_id}/${action}`, {
+                            method: 'POST',
+                            signal: activeController.signal,
+                        });
+                        if (!resumeRes.ok) throw new Error(`Resume failed: HTTP ${resumeRes.status}`);
+                        continue;
+                    }
+
                     break;
                 }