fix(web): profile save gives visible feedback (HX-Refresh)

The admin/user profile modal PUT succeeded but the response was a bare
JSON body swapped into a small div at the bottom of the still-open
modal — no close, no toast, nothing moved. It read as 'the button did
nothing' even though the save landed. HX-Request calls now answer with
HX-Refresh (re-render shows the saved values everywhere and closes the
modal) plus a visible confirmation. API callers keep the JSON body.
Silent-failure display already exists site-wide (toast.ts listens for
htmx:responseError), so failures were never the silent case.

internal/handlers/auth.go

@@ -693,6 +693,15 @@ func (h *AuthHandler) UpdateProfile(c *echo.Context) error {
 		}
 	}
 
+	// Browser path (htmx modal + profile page): refresh so every rendered
+	// value (timezone select, table rows, header) reflects the save and the
+	// modal closes. A bare JSON body swapped into #profile-result read as
+	// "nothing happened" — the save DID land, invisibly.
+	if c.Request().Header.Get("HX-Request") == "true" {
+		c.Response().Header().Set("HX-Refresh", "true")
+		return c.HTML(http.StatusOK, `<div class="text-green-500">Profile updated.</div>`)
+	}
+
 	return c.JSON(http.StatusOK, map[string]string{"message": "profile updated successfully"})
 }