Clean up stale source comments and repo noise

[peterswimm]

Amazing project! Want it through my testing harness to try out some Codex tweaks and made a little quality of life PR.

Summary

• clean up stale SMSDJ and milestone-era comments in the core assembly modules
• add clearer navigation and maintenance notes in editor.asm
• ignore and remove accidental Python cache artifacts from tools/__pycache__
• fix the stale demo song size docstring in tools/makedemo.py

Testing

• attempted make clean && make
• build is blocked locally because wla-z80 and wlalink are not on PATH
• spot-checked tools/savetool.py usage text and stale-string grep cleanup

[peterswimm]

Notes For AI-Assisted Edits

• This cleanup is also intended to reduce failure modes that show up in Claude-assisted changes: stale naming, milestone-era comments that no longer describe the current code, redundant scaffolding comments, and accidental generated-file churn.
• In this repo those issues are higher-risk than usual because the assembly sources double as working documentation for timing-sensitive, bank-sensitive, and SRAM/save-format-sensitive behavior.
• The main things to watch for in future AI-assisted edits are:
  • stale historical comments surviving after the code evolves
  • old product names or tool paths being reintroduced from outdated context
  • comment rewrites that weaken or blur hardware invariants
  • cleanup work drifting into behavioral changes in hot or timing-critical paths
  • generated/local artifacts being committed along with nearby edits

Follow-Up Questions

• Have you considered adding lightweight linting or repo checks for:
  • stale strings like SMSDJ
  • old tool-path references
  • tracked __pycache__ / *.pyc
  • doc/runtime consistency for save-format sizes and tool names
• Have you considered tightening the Claude code prompt for this repo so it explicitly requires:
  • preserving hardware, timing, banking, and save-format invariants
  • avoiding milestone/status commentary in source headers
  • treating comments as current technical documentation, not historical narration
  • keeping cleanup passes behavior-preserving unless a refactor is explicitly requested