feat(ui): overhaul default channel editor with full param override visual editor

- Port classic ParamOverrideEditorModal to default as standalone dialog (~3200 lines)
  with two-panel layout, drag-to-reorder, 23 operation modes, template library,
  visual/JSON dual mode, conditions management, and legacy format support
- Redesign channel drawer layout with clear visual hierarchy (CardHeading vs SubHeading)
  and bordered sub-modules for Field Passthrough and Upstream Model Detection
- Replace header override JsonEditor with plain textarea matching classic behavior
- Add searchable channel type combobox with scroll fix
- Add 100+ i18n keys across all 6 locales (en, zh, fr, ja, ru, vi)

web/default/src/i18n/locales/_reports/ru.untranslated.json

@@ -25,6 +25,7 @@
   "footer.columns.related.links.midjourney": "Midjourney-Proxy",
   "footer.columns.related.links.neko": "neko-api-key-tool",
   "Gemini": "Gemini",
+  "Gemini Image 4K": "Gemini Image 4K",
   "GitHub": "GitHub",
   "gpt-3.5-turbo": "gpt-3.5-turbo",
   "gpt-3.5-turbo-0125": "gpt-3.5-turbo-0125",