[codex] Harden v3.30 alert clip field-test path

[Anthonyiswhy]

Summary

• Brings the latest v3.30 generated alert clip mode onto a branch based on current main.
• Expands generated clip coverage through 3.2m and adds common awareness/info phrases, including the 2.3m field fallback seen in uploaded logs.
• Prevents BLINDNAV_ALERT_TTS=clips from silently falling back to live Piper by default for queued awareness/info speech; missing clips fall back to espeak-ng unless BLINDNAV_CLIP_MODE_ALLOW_LIVE_PIPER=1 is set.
• Adds BlindNav GitHub infrastructure: PR template, NumPy 1.26.4 pin in CI/requirements, clip directory ignore, updated field-test docs, and a Codex handoff note.
• Adds a retry path for GitHub log upload pushes if the log branch moved between clone and push.

Why

The May 13 uploaded desk log showed clip hits were fast, but also exposed a missing 2.3m phrase fallback and one Busy area awareness phrase using live Piper. This PR keeps the next field test measuring local playback latency instead of Pi-side synthesis latency.

Validation

python -m pytest tests/test_blindnav.py tests/test_blindnav_v326.py -q
# 200 passed

python -m py_compile raspberry_pi/yolo_realsense_navigation.py tools/generate_alert_clips.py tools/upload_run_logs_to_github.py tools/test_transcribe.py

python tools/generate_alert_clips.py --list
# 294 phrase(s)

Notes

• I left the existing untracked local weekly progress docs out of this branch.
• This was hardware-free validation only; Pi/RealSense/Bluetooth/ElevenLabs live generation still need field testing.