Add Google Calendar OAuth connect and disconnect

GET /api/v1/integrations/google/connect sends the browser to Google's
consent screen (calendar.events and calendar.calendarlist.readonly,
access_type=offline, prompt=consent, PKCE S256) with a state carried in a
signed __Host-mealquest_google flow cookie bound to the session.
GET /api/v1/integrations/google/callback checks the state and session,
exchanges the code, refuses a response without a refresh token
(reconnect_required) or without both scopes, seals the refresh token with
secretbox into integrations_google and sets connected_at.
DELETE /api/v1/integrations/google revokes the token at Google and clears
it; a revoke failure keeps the connection so it can be retried.

- internal/gcal: the connect service; Google endpoints are overridable and
  internal/gcal/gcaltest fakes the token and revoke endpoints.
- internal/auth: the login cookie becomes the exported FlowCookie both
  flows use (same wire format); CheckRedirect and ExchangeError are
  exported for reuse.
- internal/config: MEALQUEST_GOOGLE_CLIENT_ID and
  MEALQUEST_GOOGLE_CLIENT_SECRET_FILE, required at boot.
- DeleteIntegrationsGoogle query (sqlc regenerated); no migration, the
  integrations_google table already exists.
- deploy: compose mounts google_client_secret; .env.example and RUNBOOK
  document the Google OAuth client, its redirect URI and rotation.

Maestro task 1e9d7850-3a09-4572-b8a1-cb18cd4774cb.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/server/boot_test.go

@@ -44,6 +44,10 @@ func loadConfig(t *testing.T, keyFile string) config.Config {
 	if err := os.WriteFile(clientSecretPath, []byte("client-secret\n"), 0o600); err != nil {
 		t.Fatal(err)
 	}
+	googleSecretPath := filepath.Join(dir, "google_client_secret")
+	if err := os.WriteFile(googleSecretPath, []byte("google-secret\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
 	t.Setenv(config.EnvHTTPAddr, "127.0.0.1:0")
 	t.Setenv(config.EnvPublicURL, "http://localhost")
 	t.Setenv(config.EnvDataDir, t.TempDir())
@@ -53,6 +57,8 @@ func loadConfig(t *testing.T, keyFile string) config.Config {
 	t.Setenv(config.EnvOIDCClientID, "mealquest")
 	t.Setenv(config.EnvOIDCClientSecretFile, clientSecretPath)
 	t.Setenv(config.EnvOIDCAllowedGroups, "mealquest-admin")
+	t.Setenv(config.EnvGoogleClientID, "mealquest.apps.googleusercontent.com")
+	t.Setenv(config.EnvGoogleClientSecretFile, googleSecretPath)
 	// MEALQUEST_DEFAULT_TZ is left unset; t.Setenv restores any outer value.
 	t.Setenv(config.EnvDefaultTZ, "")
 	if err := os.Unsetenv(config.EnvDefaultTZ); err != nil {

cmd/server/main.go

@@ -21,6 +21,7 @@ import (
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/dinners"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/forwarded"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/frontend"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/gcal"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/household"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/plan"
@@ -118,6 +119,18 @@ func run(cfg config.Config, logger *slog.Logger) error {
 		return err
 	}
 
+	googleSvc, err := gcal.NewService(db, box, gcal.Config{
+		ClientID:     cfg.GoogleClientID,
+		ClientSecret: cfg.GoogleClientSecret.Reveal(),
+		PublicURL:    cfg.PublicURL,
+		SecretKey:    []byte(cfg.SecretKey.Reveal()),
+		Endpoint:     gcal.GoogleEndpoint,
+		RevokeURL:    gcal.GoogleRevokeURL,
+	})
+	if err != nil {
+		return err
+	}
+
 	sessions, err := auth.NewSessionManager(db, cfg.SessionIdle, cfg.SessionMax)
 	if err != nil {
 		return err
@@ -134,7 +147,7 @@ func run(cfg config.Config, logger *slog.Logger) error {
 		return err
 	}
 
-	router, err := server.NewRouter(logger, version, cfg.TrustedProxy, authFlow, sessions, settings, search, ai, dinnerSvc, suggestSvc, planSvc, runner, photos, frontend.Assets())
+	router, err := server.NewRouter(logger, version, cfg.TrustedProxy, authFlow, sessions, settings, search, ai, dinnerSvc, suggestSvc, planSvc, googleSvc, runner, photos, frontend.Assets())
 	if err != nil {
 		return err
 	}