feat: Add OpenWebUI Community API patterns documentation and enhance stats script to accurately count downloadable post types

.agent/learnings/openwebui-community-api.md

@@ -0,0 +1,45 @@
+# OpenWebUI Community API Patterns
+
+## Post Data Structure Variations
+
+When fetching posts from the OpenWebUI Community API (`https://api.openwebui.com/api/v1/posts/...`), the structure of the `data` field varies significantly depending on the `type` of the post.
+
+### Observed Mappings
+
+| Post Type | Data Key (under `data`) | Usual Content |
+|-----------|-------------------------|---------------|
+| `action`  | `function`              | Plugin code and metadata |
+| `filter`  | `function`              | Filter logic and metadata |
+| `pipe`    | `function`              | Pipe logic and metadata |
+| `tool`    | `tool`                  | Tool definition and logic |
+| `prompt`  | `prompt`                | Prompt template strings |
+| `model`   | `model`                 | Model configuration |
+
+### Implementation Workaround
+
+To robustly extract metadata (like `version` or `description`) regardless of the post type, the following heuristic logic is recommended:
+
+```python
+def _get_plugin_obj(post: dict) -> dict:
+    data = post.get("data", {}) or {}
+    post_type = post.get("type")
+    
+    # Priority 1: Use specific type key
+    if post_type in data:
+        return data[post_type]
+    
+    # Priority 2: Fallback to common keys
+    for k in ["function", "tool", "pipe"]:
+        if k in data:
+            return data[k]
+            
+    # Priority 3: First available key
+    if data:
+        return list(data.values())[0]
+        
+    return {}
+```
+
+### Gotchas
+- Some older posts or different categories might not have a `version` field in `manifest`, leading to empty strings or `N/A` in reports.
+- `slug` should be used as the unique identifier rather than `title` when tracking stats across history.