Codex Agent integration: HTTP surface + plugin bundle + Settings UI

This persists work that had been living only in the cookbook docker
container's writable layer — never committed to the host source. Brought
back to git intact, app.py registration re-applied surgically on top of
current main (not the older container copy, which would have regressed
the Windows MIME fix, asynccontextmanager lifespan, and webhook auth
exempts).

routes/codex_routes.py (new):
- GET  /api/codex/capabilities  — what this Odysseus exposes.
- GET  /api/codex/plugin.zip    — downloads integrations/codex as a zip.
- GET  /api/codex/todos         — scope-gated todos:read|write.
- POST /api/codex/todos         — scope-gated todos:write.
- GET  /api/codex/emails        — scope-gated email:read|draft|send.
- GET  /api/codex/emails/{uid}  — single-message fetch.
- _scope_owner() enforces api_token scopes before touching user data.

routes/api_token_routes.py (+103 lines):
- Adds Codex-token-specific issuance + revocation paths.

integrations/codex/ (new bundle, shipped via /api/codex/plugin.zip):
- README.md                       — install instructions.
- .codex-plugin/plugin.json       — Codex plugin manifest.
- scripts/odysseus_api.py         — Python client used by the skill.
- skills/odysseus/SKILL.md        — Codex skill definition.

static/js/settings.js (+253 lines):
- New "Codex Agent" option in the Integrations dropdown.
- Add / edit panel with plugin-bundle download link + curl-with-token
  install instructions per agent.

app.py:
- 7-line surgical change: capture email_router = setup_email_routes()
  and register setup_codex_routes(email_router=email_router) after the
  email module so the Codex routes can borrow its helpers.

integrations/codex/scripts/odysseus_api.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+"""Small Odysseus scoped API helper for Codex terminal sessions."""
+
+from __future__ import annotations
+
+import json
+import os
+import sys
+import urllib.error
+import urllib.request
+
+
+def _usage() -> int:
+    print("usage:", file=sys.stderr)
+    print("  odysseus_api.py capabilities", file=sys.stderr)
+    print("  odysseus_api.py todos list", file=sys.stderr)
+    print("  odysseus_api.py todos add TITLE", file=sys.stderr)
+    print("  odysseus_api.py emails list [limit]", file=sys.stderr)
+    print("  odysseus_api.py emails read UID", file=sys.stderr)
+    print("  odysseus_api.py METHOD /api/codex/path [json-body]", file=sys.stderr)
+    return 2
+
+
+def _config() -> tuple[str, str] | None:
+    base_url = os.environ.get("ODYSSEUS_URL", "").strip().rstrip("/")
+    token = os.environ.get("ODYSSEUS_API_TOKEN", "").strip()
+    missing = []
+    if not base_url:
+        missing.append("ODYSSEUS_URL")
+    if not token:
+        missing.append("ODYSSEUS_API_TOKEN")
+    if missing:
+        print(f"missing {', '.join(missing)}; create a Codex Agent token in Odysseus Settings", file=sys.stderr)
+        return None
+    return base_url, token
+
+
+def main() -> int:
+    if len(sys.argv) < 2:
+        return _usage()
+
+    command = sys.argv[1].lower()
+    if command == "capabilities":
+        method = "GET"
+        path = "/api/codex/capabilities"
+        body = None
+    elif command == "todos":
+        if len(sys.argv) < 3:
+            return _usage()
+        action = sys.argv[2].lower()
+        path = "/api/codex/todos"
+        if action == "list":
+            method = "GET"
+            body = None
+        elif action == "add" and len(sys.argv) >= 4:
+            method = "POST"
+            body = json.dumps({"action": "add", "title": " ".join(sys.argv[3:])})
+        else:
+            return _usage()
+    elif command == "emails":
+        if len(sys.argv) < 3:
+            return _usage()
+        action = sys.argv[2].lower()
+        if action == "list":
+            method = "GET"
+            limit = sys.argv[3] if len(sys.argv) >= 4 else "10"
+            path = f"/api/codex/emails?folder=INBOX&limit={limit}&offset=0&filter=all"
+            body = None
+        elif action == "read" and len(sys.argv) >= 4:
+            method = "GET"
+            path = f"/api/codex/emails/{sys.argv[3]}"
+            body = None
+        else:
+            return _usage()
+    else:
+        if len(sys.argv) < 3:
+            return _usage()
+        method = sys.argv[1].upper()
+        path = sys.argv[2]
+        body = sys.argv[3] if len(sys.argv) > 3 else None
+
+    if not path.startswith("/"):
+        path = "/" + path
+    if not path.startswith("/api/codex/"):
+        print("refusing non-/api/codex path; use scoped Odysseus integration endpoints only", file=sys.stderr)
+        return 2
+
+    config = _config()
+    if config is None:
+        return 2
+    base_url, token = config
+
+    data = None
+    headers = {
+        "Accept": "application/json",
+        "Authorization": f"Bearer {token}",
+    }
+    if body is not None:
+        try:
+            parsed = json.loads(body)
+        except json.JSONDecodeError as exc:
+            print(f"invalid json body: {exc}", file=sys.stderr)
+            return 2
+        data = json.dumps(parsed).encode("utf-8")
+        headers["Content-Type"] = "application/json"
+
+    req = urllib.request.Request(base_url + path, data=data, headers=headers, method=method)
+    try:
+        with urllib.request.urlopen(req, timeout=20) as resp:
+            print(resp.read().decode("utf-8"))
+            return 0
+    except urllib.error.HTTPError as exc:
+        text = exc.read().decode("utf-8", errors="replace")
+        print(text or f"HTTP {exc.code}", file=sys.stderr)
+        return 1
+    except OSError as exc:
+        print(f"request failed: {exc}", file=sys.stderr)
+        return 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())