feat: remove AI thumbnails, rewrite frontend with React (v1.3.0)

Remove all AI thumbnail generation infrastructure (too expensive,
poor results) and rewrite the public-facing article feed as a React
SPA mounted via WordPress shortcode.

Changes:
- Remove thumbnail generation, OG scraping, and image download code
  from fetcher, LLM, and admin classes
- Replace server-rendered PHP templates with React component
  (PeptideNewsFeed.jsx) using WordPress-bundled React/ReactDOM
- Add Babel build pipeline for JSX transpilation
- Update REST API to serve ai_summary instead of thumbnail fields
- Redesign public CSS: clean card layout, loading skeletons,
  dark mode, responsive, no thumbnail imagery
- Remove dead admin settings (llm_image_model, thumbnail_fallback)
- Fix call_openrouter() visibility for Content Filter cross-class use
- Bump version to 1.3.0

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

package.json

@@ -0,0 +1,28 @@
+{
+  "name": "repo",
+  "version": "1.0.0",
+  "description": "A WordPress plugin that aggregates and displays the latest peptide research news from multiple sources, with built-in click analytics and trend reporting.",
+  "main": "index.js",
+  "directories": {
+    "test": "tests"
+  },
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://peptiderepo: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@github.com/peptiderepo/peptide-news-plugin.git"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/peptiderepo/peptide-news-plugin/issues"
+  },
+  "homepage": "https://github.com/peptiderepo/peptide-news-plugin#readme",
+  "devDependencies": {
+    "@babel/cli": "^7.28.6",
+    "@babel/core": "^7.29.0",
+    "@babel/preset-react": "^7.28.5"
+  }
+}