Name the wayfinder unit a "decision ticket"

People kept reading a wayfinder ticket as an ordinary implementation
ticket — a slice of a build to execute — when wayfinder uses them as
decision tickets: questions whose resolution is a decision.

Introduce "decision ticket" as a light leading word: the skill
description and its opening line name it (and say what makes it one),
and the ask-matt / engineering README blurbs and the docs page match,
while "ticket" stays the everyday word once the term is established.
Record "Decision ticket" in CONTEXT.md so the "avoid: ticket" domain
rule no longer contradicts wayfinder's deliberate use of the word.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/engineering/wayfinder.md

@@ -12,7 +12,7 @@ npx skills update wayfinder
 
 ## What it does
 
-`wayfinder` takes an effort too big for one agent session — wrapped in fog, where the way from here to the goal isn't visible yet — and charts it as a **shared map** of investigation tickets on your issue tracker, then resolves them one at a time until the way is clear. It **plans, it doesn't do**: every ticket resolves a decision, and the map is done when nothing is left to decide before someone goes and builds the thing — so it produces decisions, not deliverables.
+`wayfinder` takes an effort too big for one agent session — wrapped in fog, where the way from here to the goal isn't visible yet — and charts it as a **shared map** of **decision tickets** on your issue tracker, then resolves them one at a time until the way is clear. It **plans, it doesn't do**: every ticket resolves a decision — a question to settle, not a slice of a build to execute — and the map is done when nothing is left to decide before someone goes and builds the thing — so it produces decisions, not deliverables.
 
 ## When to reach for it