fix(bin): put five skills' boundaries where the router can read them

grill-me, grill-with-docs, improve-codebase-architecture, tdd and triage each had
their routing boundary written into README.md, which nothing loads at runtime,
while the gate still reported all five descriptions as boundary-less. The
boundaries move into the descriptions; write-docs' clause, which said 'those have
dedicated skills' without naming one, now names them.

research had moved its body out and then read both references unconditionally --
the anti-goal ADR-0020 names, where the word count moves and the per-run context
does not. Both loads are genuinely conditional now, with the topic list and the
four literal sources.md field names inlined, since the provenance validator
matches those literally.

Also restores the promote-the-prototype anti-pattern to prototype's ui.md, which
the gate does not measure, so deleting it bought nothing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EJJrm5YmacbwMdzZpXcoti

plugins/bin/skills/grill-me/SKILL.md

@@ -1,6 +1,10 @@
 ---
 name: grill-me
-description: Interview the user relentlessly about a plan or design until reaching shared understanding, resolving each branch of the decision tree. Use when user wants to stress-test a plan, get grilled on their design, or mentions "grill me".
+description: >
+  Use when the user says "grill me" or wants a plan or design stress-tested by
+  relentless interview — one question at a time, down each branch of the
+  decision tree. Not a plan to challenge against `CONTEXT.md` and ADRs ->
+  `grill-with-docs`.
 ---
 
 Interview me relentlessly about every aspect of this plan until we reach a shared understanding. Walk down each branch of the design tree, resolving dependencies between decisions one-by-one. For each question, provide your recommended answer.