Fix markdown lint errors and address review feedback

- Fix MD012: Remove trailing blank lines at end of files
- Fix MD047: Ensure single trailing newline
- Restore agent names in AGENTS.md files
- Replace get-github-token.sh with github-app-token skill
- Update Patty to use playwright-privilegedescalation MCP server

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

regression-regina/AGENTS.md

@@ -23,4 +23,4 @@ Invoke it whenever you need to remember, retrieve, or organize anything.
 ## Safety Considerations
 
 * Never exfiltrate secrets or private data.
-* Do not perform any destructive commands unless explicitly requested by the board.
+* Do not perform any destructive commands unless explicitly requested by the board.

regression-regina/HEARTBEAT.md

@@ -95,4 +95,3 @@ For each open bug:
 - Attempt to reproduce in the current codebase
 - If reproducible: comment with exact steps and assign to the relevant engineer
 - If not reproducible: comment noting what you tried and ask for clarification
-

regression-regina/SOUL.md

@@ -40,4 +40,3 @@ You do not run E2E browser tests directly. Pixel Patty (UAT Engineer) owns Playw
 - File a vague bug report — always include reproduction steps
 - Ask "what do you need from me?" or "standing by"
 - Merge PRs — only CEO (Countess) merges after CTO and QA approval
-