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>

mempalace/split_mega_files.py

@@ -219,7 +219,7 @@ def split_file(filepath, output_dir, dry_run=False):
         if dry_run:
             print(f"  [{i + 1}/{len(boundaries) - 1}] {name}  ({len(chunk)} lines)")
         else:
-            out_path.write_text("".join(chunk))
+            out_path.write_text("".join(chunk), encoding="utf-8")
             print(f"  ✓ {name}  ({len(chunk)} lines)")
 
         written.append(out_path)