feat(tunnel,ui): purple tunnel button + opt-in unauthenticated tunnel with warning (v1.1.9)

- Daylight Blue: Cloudflare Tunnel welcome button is now purple (was orange),
  keeping Claude blue / Tunnel purple / OpenCode green distinct.
- Allow enabling the Cloudflare tunnel with no CODEMAN_PASSWORD via the UI: the
  toggle now pops a security confirm dialog and, on confirm, sends an explicit
  per-request acknowledgeUnauthTunnel:true (new action field, never persisted).
  Server logs a loud warning whenever a passwordless public tunnel starts.
  curl/API/CLI stay refused unless password/env/flag — no accidental exposure.

Tests: extend test/routes/system-routes-tunnel-guard.test.ts (ack allows + not
persisted; ack:false still refuses). Verified e2e on an isolated instance
(purple button, confirm dialog, retry carries the flag, no real tunnel opened).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/web/public/settings-ui.js

@@ -1176,6 +1176,48 @@ Object.assign(CodemanApp.prototype, {
     } catch {
       /* non-JSON body — use the default message */
     }
+    // 403 = the no-password safety refusal (COD-55). Warn loudly and let the
+    // operator acknowledge the risk; on confirm, retry with explicit acknowledgment.
+    if (res.status === 403) {
+      const confirmed = confirm(
+        '⚠️ SECURITY WARNING — no password set\n\n' +
+          'Enabling the Cloudflare tunnel will publish THIS machine to a public URL with ' +
+          'NO login. Anyone who gets the URL has full terminal control — effectively remote ' +
+          'code execution on your computer.\n\n' +
+          'Strongly recommended: set CODEMAN_PASSWORD instead.\n\n' +
+          'Enable the unauthenticated public tunnel anyway?'
+      );
+      if (!confirmed) {
+        this._dismissTunnelConnecting?.();
+        this.showToast('Tunnel not enabled', 'info');
+        return true;
+      }
+      try {
+        const retry = await fetch('/api/settings', {
+          method: 'PUT',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ tunnelEnabled: true, acknowledgeUnauthTunnel: true }),
+        });
+        if (retry.ok) {
+          this.showToast('Public tunnel enabling — no password set ⚠️', 'warning');
+          return false; // proceed with the caller's success/connecting path
+        }
+        let m = 'Failed to enable tunnel.';
+        try {
+          const b = await retry.json();
+          if (b && b.error) m = b.error;
+        } catch {
+          /* non-JSON */
+        }
+        this._dismissTunnelConnecting?.();
+        this.showToast(m, 'error');
+        return true;
+      } catch {
+        this._dismissTunnelConnecting?.();
+        this.showToast('Failed to enable tunnel', 'error');
+        return true;
+      }
+    }
     this._dismissTunnelConnecting?.();
     this.showToast(message, 'error');
     return true;