added local export support and refined program logic

examples.md

@@ -10,6 +10,7 @@ Root directory manifest (`.wp-materialize.json`):
 {
   "categories": { "content": ["Systems", "Infrastructure"], "inherit": true },
   "tags": { "content": ["automation", "wordpress"], "inherit": true },
+  "author": { "content": ["editorial"], "inherit": true },
   "subdirectories": { "content": ["design", "notes"], "inherit": true },
   "files": {
     "post.md": {
@@ -18,7 +19,9 @@ Root directory manifest (`.wp-materialize.json`):
       "tags": { "content": ["extra"], "inherit": true }
     },
     "essay.md": {
-      "use_heading_as_title": { "level": 1, "strict": true }
+      "use_heading_as_title": { "level": 1, "strict": true },
+      "created_on": "2025-01-10 09:30",
+      "last_modified": "2025-02-14 16:45"
     }
   }
 }
@@ -103,3 +106,8 @@ Subdirectory manifest (`design/.wp-materialize.json`):
   "directories": []
 }
 ```
+
+## Timestamp Behavior Example
+
+- `git_repositories` entries use git commit timestamps for `created_on`/`last_modified` inference.
+- `directories` entries use filesystem timestamps even if the path is inside a git repo.