fix(auth): GetProfile reads the user row — the JWT context stub has no theme

GetProfile returned the theme from the JWT-claims context stub, which
carries only id/email/username/role — user.Theme was always empty, so
the profile response omitted the field and the app's account-theme
read-back (SERVER sync mode) could never see the stored theme. GetProfile
now loads the full user row by id (h.db.GetUser).

internal/handlers/auth.go

@@ -486,7 +486,14 @@ window.location.href = '%s';
 
 // GetProfile handles GET /api/auth/profile
 func (h *AuthHandler) GetProfile(c *echo.Context) error {
-	user := MustGetAuthenticatedUser(c)
+	ctxUser := MustGetAuthenticatedUser(c)
+	// The context user is a JWT-claims stub (id/email/username/role) —
+	// it carries no theme. Read the full row: clients (the Android app)
+	// sync their app-chrome theme from this field.
+	user, err := h.db.GetUser(c.Request().Context(), ctxUser.ID)
+	if err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to load profile"})
+	}
 
 	firstName := ""
 	if user.FirstName.Valid {