fix(pebble): ASCII-coerce ntfy title; disambiguate STT against KB folders

[ClaydeCode]

Summary

• Bug: Pebble request `c37ef27f` (2026-05-17 18:37) finished successfully and wrote `inbox/thomas_stegger_note.md`, but the ntfy notification with title `"Thomas Stegger — plant prefs saved"` was silently dropped:

  ntfy POST failed: 'ascii' codec can't encode character '—' in position 15: ordinal not in range(128)
  

  httpx encodes header values as latin-1, so any Unicode character outside that range (em dash, smart quotes, ellipsis, NBSP, emoji, …) raises `UnicodeEncodeError` before the request goes out. Watch shows "delivered" (enqueue 200), then nothing — so it looks like Clayde swallowed the call.
• Fix: Normalise common typographic Unicode in `NotificationPayload.title` (em/en dash, smart quotes, ellipsis, NBSP) and ASCII-replace anything left over. Done in the field validator, so all callers (parsed Claude tail, framework fallback titles) are covered. Applied before length clamping so `…` → `...` doesn't blow past 40 chars.
• Bonus: Tighten the Pebble system prompt so STT errors are disambiguated against the KB's real folder layout. Worked example: `"after people and tree for my brother-in-law"` → `"add a people entry for my brother-in-law"`, because `people/` is a real top-level folder and "after" / "tree" are plausible phonetic neighbours of "add a" / "entry". Claude is told to `ls /home/clayde/knowledge_base` and to state the chosen interpretation in its narrative so a wrong guess is visible in the ntfy summary.

Test plan

• `uv run pytest` — 368 passed locally
• Added regression tests in `test_webhook_notify.py`: em dash, smart quotes, emoji, ASCII-coercion-before-clamp
• Added prompt assertions in `test_webhook_skills.py`: KB-structure disambiguation guidance present
• Manual: send a pebble whose summary will contain an em dash, confirm watch notification arrives

🤖 Generated with Claude Code