Refine coding standards and testing guidelines

- Updated coding rule descriptions for clarity and emphasis on readability, meaningful comments, and test verification.
- Adjusted thresholds for test coverage on business logic from 80% to 75%, aligning with the canonical reference in `cursor-meta.mdc`.
- Enhanced guidelines for handling skipped tests, emphasizing the need for investigation and classification.
- Introduced completeness audit requirements for research decomposition to ensure thoroughness in addressing problem dimensions.

.cursor/skills/autopilot/SKILL.md

@@ -55,6 +55,11 @@ After selecting the flow, apply its detection rules (first match wins) to determ
 Every invocation follows this sequence:
 
 ```
+0. Process leftovers (see `.cursor/rules/tracker.mdc` → Leftovers Mechanism):
+   - Read _docs/_process_leftovers/ if it exists
+   - For each entry, attempt replay against the tracker
+   - Delete successful replays, update failed ones with new timestamp + reason
+   - If any leftover still blocked AND requires user input → STOP and ASK
 1. Read _docs/_autopilot_state.md (if exists)
 2. Read all File Index files above
 3. Cross-check state file against _docs/ folder structure (rules in state.md)