Fold recursion in the HUD breadcrumb and open the local map at start

[valuecodes]

What

• Part 1/5 of Post-MVP additions: direct recursion folds into one breadcrumb entry, main() → countdown() ×3 ↻, instead of repeating the function once per frame.
• Mutual recursion (a → b → a) stays spelled out, because its frames are not consecutive.
• Stacks deeper than six entries keep the first caller, … and the last four, so the HUD line stays short.
• The local map (M) is open at start; M hides it. The README controls table says so.

How to test

pnpm test
pnpm --filter web dev

Open http://localhost:3000/?code=portals, walk from main() through its door into countdown(), take the recursive portal twice and read the breadcrumb.

Security review

No security-impacting changes.

🤖 Generated with Claude Code

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-13T18:41:40.668266Z	2755ca9	PR opened

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