GRM-36: fix: use correct Gitea 1.26 wiki API endpoints

Updated sync_wiki.py to use correct Gitea 1.26 wiki API: POST /wiki/new for create, PATCH /wiki/page/{sub_url} for update, GET /wiki/pages returns sub_url. Tests updated to match.

Closes GRM-36

scripts/sync_wiki.py

@@ -6,6 +6,12 @@ map file paths to wiki page titles, and creates/updates wiki pages via the
 Gitea API.  Pages that exist in the wiki but not in the mapping are left
 untouched (not deleted).
 
+Gitea 1.26 wiki API endpoints:
+  - Create: POST /repos/{owner}/{repo}/wiki/new  {title, content, message}
+  - Update: PATCH /repos/{owner}/{repo}/wiki/page/{sub_url}  {title, content, message}
+  - List:   GET /repos/{owner}/{repo}/wiki/pages  → [{title, sub_url, ...}]
+  - Delete: DELETE /repos/{owner}/{repo}/wiki/page/{sub_url}
+
 Usage:
   REPO_TOKEN=<token> python3 scripts/sync_wiki.py [--dry-run] [--repo owner/repo]
 """
@@ -44,12 +50,12 @@ def read_doc_content(file_path: str) -> str:
 
 
 def list_wiki_pages(client: GiteaClient) -> dict[str, str]:
-    """List existing wiki pages, returning {title: page_name}."""
+    """List existing wiki pages, returning {title: sub_url}."""
     try:
         pages = client._request("GET", "/wiki/pages").json()
     except APIError:
         return {}
-    return {page.get("title", ""): page.get("page_name", page.get("title", "")) for page in pages}
+    return {page.get("title", ""): page.get("sub_url", page.get("title", "")) for page in pages}
 
 
 def sync_page(
@@ -68,19 +74,19 @@ def sync_page(
         return "skipped"
 
     if page_title in existing_pages:
-        # Update existing page
-        page_name = existing_pages[page_title]
+        # Update existing page via PATCH
+        sub_url = existing_pages[page_title]
         client._request(
-            "PUT",
-            f"/wiki/page/{page_name}",
-            json={"content": content, "message": f"Sync from docs/ — update {page_title}"},
+            "PATCH",
+            f"/wiki/page/{sub_url}",
+            json={"title": page_title, "content": content, "message": f"Sync from docs/ — update {page_title}"},
         )
         return "updated"
 
-    # Create new page
+    # Create new page via POST /wiki/new
     client._request(
         "POST",
-        "/wiki/page",
+        "/wiki/new",
         json={"title": page_title, "content": content, "message": f"Sync from docs/ — create {page_title}"},
     )
     return "created"