refactor: Replace generator with enhanced version

- Extracts full frontmatter metadata (originalDate, notion_*, authors, source)
- Correct date priority: frontmatter → filename → mtime → ctime
- All metadata exposed in index.json for frontend use

Phase 1 quick win complete.

package-lock.json

@@ -0,0 +1,37 @@
+{
+  "name": "the-fold-within",
+  "version": "3.0.2",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "the-fold-within",
+      "version": "3.0.2",
+      "dependencies": {
+        "pdf-parse": "^1.1.4"
+      }
+    },
+    "node_modules/node-ensure": {
+      "version": "0.0.0",
+      "resolved": "https://registry.npmjs.org/node-ensure/-/node-ensure-0.0.0.tgz",
+      "integrity": "sha512-DRI60hzo2oKN1ma0ckc6nQWlHU69RH6xN0sjQTjMpChPfTYvKZdcQFfdYK2RWbJcKyUizSIy/l8OTGxMAM1QDw==",
+      "license": "MIT"
+    },
+    "node_modules/pdf-parse": {
+      "version": "1.1.4",
+      "resolved": "https://registry.npmjs.org/pdf-parse/-/pdf-parse-1.1.4.tgz",
+      "integrity": "sha512-XRIRcLgk6ZnUbsHsYXExMw+krrPE81hJ6FQPLdBNhhBefqIQKXu/WeTgNBGSwPrfU0v+UCEwn7AoAUOsVKHFvQ==",
+      "license": "MIT",
+      "dependencies": {
+        "node-ensure": "^0.0.0"
+      },
+      "engines": {
+        "node": ">=6.8.1"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/mehmet-kozan"
+      }
+    }
+  }
+}