Fix Autoloop creating a new branch+PR per iteration instead of reusing one per program

[Copilot]

Autoloop was appending random hashes to branch names (e.g. autoloop/coverage-deadbeef1234) and creating a new draft PR each iteration, violating the one-branch-one-PR-per-program invariant.

Agent instruction fixes (autoloop.md)

• Branch naming: Added explicit ⚠️ CRITICAL callout — branch must be EXACTLY autoloop/{program-name}, no suffixes/hashes/run-IDs. Includes concrete ❌ counter-examples and a git snippet for the check-out-or-create pattern.
• PR lookup before creation: Step 1 now explicitly reads the PR field from the state file's Machine State table. Step 5 now has a 4-step lookup procedure:
  1. Check PR field in state file
  2. If missing, query GitHub API for open PRs with head=autoloop/{program-name}
  3. If found → push-to-pull-request-branch (never create-pull-request)
  4. If not found → create-pull-request with the explicit branch name
• Common Mistakes to Avoid: New section with ❌/✅ rules covering branch naming, duplicate PRs, and auto-generated branch names.

Safety constraint changes

Reduced max for both create-pull-request and push-to-pull-request-branch from 2 → 1 in both autoloop.md frontmatter and the compiled autoloop.lock.yml, preventing the framework from allowing more than one PR creation per run as a hard backstop.

[mrjf]

@copilot fix CI

[Copilot]

@copilot fix CI

Fixed in 4103970. Two TypeScript errors in tests/stats/nlargest.test.ts and tests/stats/rank.test.ts were causing the CI failure — both helper functions passed undefined for optional name/index properties, which is invalid with exactOptionalPropertyTypes: true. Changed to use conditional spread (...(x !== undefined ? { x } : {})) to omit the property entirely when undefined.

[mrjf]

@copilot resolve conflicts

[Copilot]

@copilot resolve conflicts

Resolved in ce97623. Merged origin/main into the branch — the only conflicts were in tests/stats/nlargest.test.ts and tests/stats/rank.test.ts, where I kept the exactOptionalPropertyTypes fixes. Typecheck passes cleanly.