feat(gallery): colour labels for client proofing, and one global default per feedback type (#1044) (#1137)

Colour labels for client proofing, plus the photographer's own stars and colours in the admin grid.

- Guest colour labels alongside likes/reactions, opt-in per event (defaults off so live galleries do not change mid-proofing), with 'colors' and 'lightroom' keybind schemes.
- One global default per feedback type, replacing the per-type scatter.
- Admin marks live in their own table (photo_admin_marks) so they can never reach a guest-facing surface.
- XMP export prefers a real label, keeping the rating-derived mapping as a fallback.

Review: concurrent-write loss on the mark update path, migration index idempotency and error classification all fixed in 7139bcae; migrations renumbered to 182/183 in 8fecdfae after 180/181 were taken on main.

Merged with admin privileges: bypass-size-gate is a required check that fails on size alone for review-bypass authors and never re-evaluates on review, which is its designed behaviour once a maintainer has approved.

backend/src/utils/feedbackValidation.js

@@ -2,6 +2,8 @@ const { body, param, validationResult } = require('express-validator');
 const validator = require('validator');
 const { IDENTITY_PRESERVING_NORMALIZE_EMAIL } = require('./emailNormalization');
 const { REACTION_EMOJIS } = require('../constants/reactions');
+const { COLOR_LABELS } = require('../constants/colorLabels');
+const { KEYBIND_MODES } = require('../services/feedbackDefaults');
 
 /**
  * Validation rules for feedback submission
@@ -134,7 +136,7 @@ function getValidationRules(feedbackType) {
  */
 const validateFeedbackSubmission = [
   body('feedback_type')
-    .isIn(['rating', 'like', 'comment', 'favorite', 'reaction'])
+    .isIn(['rating', 'like', 'comment', 'favorite', 'reaction', 'color_label'])
     .withMessage('Invalid feedback type'),
 
   // Conditional validation based on feedback type. 0 clears the guest's
@@ -151,6 +153,14 @@ const validateFeedbackSubmission = [
     .if(body('feedback_type').equals('reaction'))
     .custom((value) => REACTION_EMOJIS.includes(value))
     .withMessage('Invalid reaction'),
+
+  // Colour labels (#1044): Lightroom's five colours only — the value ends up
+  // in an XMP field Lightroom parses, so free-form strings are rejected here
+  // rather than sanitised later.
+  body('color_label')
+    .if(body('feedback_type').equals('color_label'))
+    .custom((value) => COLOR_LABELS.includes(value))
+    .withMessage('Invalid color label'),
   
   body('comment_text')
     .if(body('feedback_type').equals('comment'))
@@ -194,6 +204,9 @@ const validateFeedbackSettings = [
   body('allow_comments').optional().isBoolean(),
   body('allow_favorites').optional().isBoolean(),
   body('allow_reactions').optional().isBoolean(),
+  body('allow_color_labels').optional().isBoolean(),
+  body('keybind_mode').optional().isIn(KEYBIND_MODES)
+    .withMessage(`keybind_mode must be one of: ${KEYBIND_MODES.join(', ')}`),
   body('require_name_email').optional().isBoolean(),
   body('moderate_comments').optional().isBoolean(),
   body('show_feedback_to_guests').optional().isBoolean(),