Add Google Calendar connector (gcal)

- connector.json: OAuth Google, scope https://www.googleapis.com/auth/calendar
  deliver: file/google_authorized_user → {secrets}/google_creds.json
  mcp_config.env.GOOGLE_CREDS_PATH = {secrets}/google_creds.json
- verify.py: loads creds + API probe (calendarList.list)
- gcal_mcp_server.py: 8 tools (status, list_calendars, list_events,
  get_event, create_event, update_event, delete_event, respond_to_event)
  + push notification polling
- icons: calendar SVG (48px + 96px)
- connectors.json index: gcal entry with auth + sha256
- SKALD.md: tabella connector + stato verify aggiornati

connectors/gcal/verify.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+"""Verify Google Calendar OAuth credentials are valid.
+
+Reads GOOGLE_CREDS_PATH env var (or falls back to secrets/google_creds.json),
+loads the authorized_user credentials, and does one cheap API probe
+(calendarList.list(maxResults=1)).
+
+Output: single JSON object on stdout:
+  {"ok": true, "message": "..."}
+  {"ok": false, "message": "..."}
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import sys
+
+
+def main() -> None:
+    creds_path = os.environ.get(
+        "GOOGLE_CREDS_PATH",
+        os.path.join(os.path.dirname(__file__), "secrets", "google_creds.json"),
+    )
+
+    if not os.path.exists(creds_path):
+        _fail(f"Credentials file not found at {creds_path}. Run gcal_oauth_setup.py first.")
+        return
+
+    try:
+        from google.auth.transport.requests import Request
+        from google.oauth2.credentials import Credentials
+        from googleapiclient.discovery import build
+    except ImportError as e:
+        _fail(f"Missing dependencies: {e}. Install google-api-python-client and google-auth.")
+        return
+
+    try:
+        creds = Credentials.from_authorized_user_file(
+            creds_path,
+            ["https://www.googleapis.com/auth/calendar"],
+        )
+    except Exception as e:
+        _fail(f"Failed to load credentials: {e}")
+        return
+
+    if creds.expired and creds.refresh_token:
+        try:
+            creds.refresh(Request())
+            with open(creds_path, "w") as f:
+                f.write(creds.to_json())
+        except Exception as e:
+            _fail(f"Token refresh failed: {e}. Re-run gcal_oauth_setup.py.")
+            return
+
+    try:
+        service = build("calendar", "v3", credentials=creds)
+        result = service.calendarList().list(maxResults=1).execute()
+        items = result.get("items", [])
+        primary = next((c for c in items if c.get("primary")), None)
+        account = primary.get("id", "?") if primary else "?"
+        _ok(f"Google Calendar credentials valid. Account: {account}")
+    except Exception as e:
+        _fail(f"API probe failed: {e}")
+
+
+def _ok(message: str) -> None:
+    json.dump({"ok": True, "message": message}, sys.stdout)
+
+
+def _fail(message: str) -> None:
+    json.dump({"ok": False, "message": message}, sys.stdout)
+    sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()