Graduate wayfinder to engineering; unify changesets for v1.1

Graduate `wayfinder` out of in-progress into the engineering bucket
(plugin.json, top-level + Engineering READMEs under User-invoked, docs
page, ask-matt on-ramp, disable-model-invocation).

Consolidate the 22 pending changesets into 10 coherent v1.1 entries:
one `wayfinder` (rename from decision-mapping + full reframe +
graduation), one `grilling`, one `code-review`, one `tdd`; fold the
superseded to-issues changeset into unify-to-tickets and drop its stray
`</content>` tag. Highest bump is minor → 1.0.1 becomes 1.1.0.

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

skills/engineering/ask-matt/SKILL.md

@@ -41,6 +41,8 @@ A starting situation that generates work, then merges onto the main flow.
 
 - **Something's broken** → **`/diagnosing-bugs`**. For the hard ones: the bug that resists a first glance, the intermittent flake, the regression that crept in between two known-good states. It refuses to theorise until it has a **tight feedback loop** — one command that already goes red on *this* bug — then fixes with a regression test. Its post-mortem hands off to **`/improve-codebase-architecture`** when the real finding is that there's no good seam to lock the bug down.
 
+- **A huge, foggy effort — too big for one session** → **`/wayfinder`**. When the way from here to the destination isn't visible yet, it charts a **shared map** of investigation tickets on the issue tracker and resolves them one at a time — producing **decisions, not deliverables** — until the fog is pushed back and the way is clear. Then it merges onto the main flow at **`/to-spec`** (or, if the effort turned out small enough, straight to **`/implement`**). Where **`/grill-with-docs`** sharpens an idea you can hold in one session, wayfinder is for the idea you can't.
+
 ## Codebase health
 
 Not feature work — upkeep.