fix(web): resolve file upload config lookup for server-rendered forms (#279)

* fix(web): resolve file upload config lookup for server-rendered forms

The file upload widget's getUploadConfig() function failed to map
server-rendered field IDs (e.g., "static-image-images") back to schema
property keys ("images"), causing upload config (plugin_id, endpoint,
allowed_types) to be lost. This could prevent image uploads from
working correctly in the static-image plugin and others.

Changes:
- Add data-* attributes to the Jinja2 file-upload template so upload
  config is embedded directly on the file input element
- Update getUploadConfig() in both file-upload.js and plugins_manager.js
  to read config from data attributes first, falling back to schema lookup
- Remove duplicate handleFiles/handleFileDrop/handleFileSelect from
  plugins_manager.js that overwrote the more robust file-upload.js versions
- Bump cache-busting version strings so browsers fetch updated JS

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(web): harden file upload functions against CodeRabbit patterns

- Add response.ok guard before response.json() in handleFiles,
  deleteUploadedFile, and handleCredentialsUpload to prevent
  SyntaxError on non-JSON error responses (PR #271 finding)
- Remove duplicate getUploadConfig() from plugins_manager.js;
  file-upload.js now owns this function exclusively
- Replace innerHTML with textContent/DOM methods in
  handleCredentialsUpload to prevent XSS (PR #271 finding)
- Fix redundant if-check in getUploadConfig data-attribute reader

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(web): address CodeRabbit findings on file upload widget

- Add data-multiple="true" discriminator on array file inputs so
  handleFileDrop routes multi-file drops to handleFiles() not
  handleSingleFileUpload()
- Duplicate upload config data attributes onto drop zone wrapper so
  getUploadConfig() survives progress-helper DOM re-renders that
  remove the file input element
- Clear file input in finally block after credentials upload to allow
  re-selecting the same file on retry
- Branch deleteUploadedFile on fileType: JSON deletes remove the DOM
  element directly instead of routing through updateImageList() which
  renders image-specific cards (thumbnails, scheduling controls)

Addresses CodeRabbit findings on PR #279:
- Major: drag-and-drop hits single-file path for array uploaders
- Major: config lookup fails after first upload (DOM node removed)
- Minor: same-file retry silently no-ops
- Major: JSON deletes re-render list as images

Co-Authored-By: 5ymb01 <5ymb01@users.noreply.github.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(web): address CodeRabbit round-2 findings on file upload widget

- Extract getConfigSourceElement() helper so handleFileDrop,
  handleSingleFileUpload, and getUploadConfig all share the same
  fallback logic: file input → drop zone wrapper
- Remove pluginId gate from getUploadConfig Strategy 1 — fields with
  uploadEndpoint or fileType but no pluginId now return config instead
  of falling through to generic defaults
- Fix JSON delete identifier mismatch: use file.id || file.category_name
  (matching the renderer at line 3202) instead of f.file_id; remove
  regex sanitization on DOM id lookup (renderer doesn't sanitize)

Addresses CodeRabbit round-2 findings on PR #279:
- Major: single-file uploads bypass drop-zone config fallback
- Major: getUploadConfig gated on data-plugin-id only
- Major: JSON delete file identifier mismatch vs renderer

Co-Authored-By: 5ymb01 <5ymb01@users.noreply.github.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(web): align delete handler file identifier with renderer logic

Remove f.file_id from JSON file delete filter to match the renderer's
identifier logic (file.id || file.category_name || idx). Prevents
deleted entries from persisting in the hidden input on next save.

Co-Authored-By: 5ymb01 <noreply@github.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: 5ymb01 <5ymb01@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: 5ymb01 <noreply@github.com>

web_interface/templates/v3/base.html

@@ -4988,7 +4988,7 @@
     <script src="{{ url_for('static', filename='v3/js/widgets/registry.js') }}" defer></script>
     <script src="{{ url_for('static', filename='v3/js/widgets/base-widget.js') }}" defer></script>
     <script src="{{ url_for('static', filename='v3/js/widgets/notification.js') }}" defer></script>
-    <script src="{{ url_for('static', filename='v3/js/widgets/file-upload.js') }}" defer></script>
+    <script src="{{ url_for('static', filename='v3/js/widgets/file-upload.js') }}?v=20260307" defer></script>
     <script src="{{ url_for('static', filename='v3/js/widgets/checkbox-group.js') }}" defer></script>
     <script src="{{ url_for('static', filename='v3/js/widgets/custom-feeds.js') }}" defer></script>
     <script src="{{ url_for('static', filename='v3/js/widgets/array-table.js') }}" defer></script>
@@ -5014,7 +5014,7 @@
     <script src="{{ url_for('static', filename='v3/js/widgets/plugin-loader.js') }}" defer></script>
     
     <!-- Legacy plugins_manager.js (for backward compatibility during migration) -->
-    <script src="{{ url_for('static', filename='v3/plugins_manager.js') }}?v=20260216b" defer></script>
+    <script src="{{ url_for('static', filename='v3/plugins_manager.js') }}?v=20260307" defer></script>
     
     <!-- Custom feeds table helper functions -->
     <script>