Release hygiene: keep internal reports out of public root

[devYRPauli]

The repo root accumulated ~30 internal development artifacts (per-cycle analysis
reports, readiness docs, release-process checklists). They cluttered the public
root and embedded real project/identity names from the local corpus used during
development. They have been removed from the current tree; this issue tracks
preventing recurrence.

Checklist

• Keep the repo root limited to standard public docs (README, CHANGELOG, CONTRIBUTING, ARCHITECTURE, LICENSE)
• Store future benchmark/dev reports under a local-only, git-ignored path (e.g. reports/ or /tmp)
• Add a .gitignore entry for internal reports (e.g. *_REPORT.md, *_READINESS.md, *_EVALUATION.md)
• (Optional) Add a pre-release check that fails if *_REPORT.md or *_READINESS.md appears in the repo root

Notes

• Generated reports often quote real project names and paths from the author's
  machine; keep them out of anything that gets committed.
• The four published release descriptions (v1.0.0, v1.5.0, v1.6.0, v2.0.0) were
  reviewed and edited to drop references to the removed internal report files.