refactor(core): modularize monolithic routers and methods

- Reduced api_crud.py (1843 -> 143 lines) by extracting V1 registry and logic.
- Reduced hosted_file.py (1596 -> 361 lines) by moving storage and media logic to methods.
- Created lib_media.py for specialized video/image processing.
- Created api_crud_methods.py for legacy template handlers.
- Created legacy_v1.py for the legacy object registry.
- Fixed subdirectory_path bug in Hosted File creation.
- Verified full File Lifecycle via consolidated E2E suite.

tests/e2e/test_e2e_v3_actions_file_lifecycle.py

@@ -63,7 +63,12 @@ def test_file_lifecycle():
 
     # 4. DELETE (Clean Cleanup)
     print("\n[Step 4] Deleting test file (rm_orphan=true)...")
-    del_params = {"rm_orphan": "true", "method": "delete"}
+    del_params = {
+        "link_to_type": LINK_TYPE,
+        "link_to_id": LINK_ID,
+        "rm_orphan": "true", 
+        "method": "delete"
+    }
     del_resp = requests.delete(f"{API_BASE}/hosted_file/{file_id}", headers=get_headers(), params=del_params)
     if del_resp.status_code == 200:
         print(f"  ✅ Deletion request successful.")