test: bring coverage to 85%, set threshold to 85, reset version to 3.0.11

- Add tests for config, convo_miner, spellcheck, knowledge_graph
- Fix Windows PermissionError in test cleanup (chromadb file locks)
- Add UTF-8 encoding to split_mega_files, entity_registry, hooks_cli
- Fix mcp_server parse_known_args logging for unknown args
- Set coverage threshold to 85 in pyproject.toml and CI
- Reset all version files to 3.0.11

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_convo_miner.py

@@ -23,4 +23,4 @@ def test_convo_mining():
     results = col.query(query_texts=["memory persistence"], n_results=1)
     assert len(results["documents"][0]) > 0
 
-    shutil.rmtree(tmpdir)
+    shutil.rmtree(tmpdir, ignore_errors=True)