Complete Phase 9: Final validation for identifier standardization

- Fix search API key extraction from link slugs
- All 1006 tests pass
- All 19 performance tests pass
- Manual end-to-end testing verified
- Key lookup performance: O(1) ~0.11μs per lookup

Phase 9 tasks completed:
- Task 9.1: Full test suite validation
- Task 9.2: Manual end-to-end testing
- Task 9.3: Performance testing

All identifier standardization phases (1-9) now complete.

docs/README.md

@@ -103,10 +103,10 @@ Production deployment instructions covering:
 
 The application uses two identifiers for anime series:
 
-| Identifier | Purpose                  | Example                    | Used For          |
-| ---------- | ------------------------ | -------------------------- | ----------------- |
-| `key`      | **Primary identifier**   | `"attack-on-titan"`        | All API lookups   |
-| `folder`   | Filesystem metadata only | `"Attack on Titan (2013)"` | Display purposes  |
+| Identifier | Purpose                  | Example                    | Used For         |
+| ---------- | ------------------------ | -------------------------- | ---------------- |
+| `key`      | **Primary identifier**   | `"attack-on-titan"`        | All API lookups  |
+| `folder`   | Filesystem metadata only | `"Attack on Titan (2013)"` | Display purposes |
 
 ### Key Format
 
@@ -129,9 +129,10 @@ GET /api/anime/Attack%20on%20Titan%20(2013)  # Will work but deprecated
 ### Backward Compatibility
 
 For existing integrations, folder-based lookups are still supported but deprecated:
-- API endpoints check `key` first, then fall back to `folder`
-- New code should always use `key` as the identifier
-- Deprecation warnings will be added in future versions
+
+-   API endpoints check `key` first, then fall back to `folder`
+-   New code should always use `key` as the identifier
+-   Deprecation warnings will be added in future versions
 
 ## Documentation Examples
 

docs/api_reference.md

@@ -791,7 +791,8 @@ ws.onmessage = (event) => {
     }
 }
 ```
-```
+
+````
 
 ---
 
@@ -803,7 +804,7 @@ Checks if the application is running.
 
 ```http
 GET /health
-```
+````
 
 **Response (200 OK)**: