Harden repository quality gates

[Y1hsiaochunnn]

Summary

• add a self-contained Markdown audit for ownership, bilingual navigation, local/reference/HTML links and fragments, homepage structure, public-text hygiene, and documentation-only scope
• make changed-file routing rename-aware and fail closed on missing, empty, malformed, or unavailable diff data
• restrict documentation-only asset exceptions to explicit repository-relative image files
• pass selected example paths through environment variables to avoid shell interpolation
• expand routing and audit regression coverage, update paired CI documentation, and replace pull request template placeholders

Scope

• preserves the ESP-IDF v5.5.5 and v6.0.2 matrix for all six first-party projects
• preserves Arduino-ESP32 3.3.11 coverage for all eight first-party sketches
• does not change example source, hardware definitions, managed component ranges, schematics, or checked-in firmware/archive artifacts

Validation

Final candidate: e67f53f679f352d7e59b5f0215eed473a549cd0e

• Build Examples #12 — completed successfully on the final candidate SHA
• quality, changed-scope classification, and both discovery jobs — passed
• ESP-IDF matrix — 12/12 passed: six projects on v5.5.5 and v6.0.2
• Arduino matrix — 8/8 passed on Arduino-ESP32 3.3.11
• stable example validation aggregate — passed
• pull-request release publication — skipped as designed
• python3 -m unittest discover -s tests -v — 59 tests passed
• repository and baseline Markdown audits — 0 errors, 0 warnings
• deterministic CI routing audit — six ESP-IDF projects and eight Arduino sketches selected; documentation-only false
• git diff --check origin/main...HEAD — passed
• checked-in firmware binary and schematic hashes — unchanged
• local product builds: waived by user