chore: re-sync agent skills to upstream mattpocock/skills

Local snapshots dated 2026-09-16; upstream has moved on since. Refreshes
7 SKILL.md files (code-review, diagnosing-bugs, implement, tdd, grilling,
handoff, teach): tracker-doc references generalized, CONTEXT.md renamed
GLOSSARY.md, implement gains ticket-fetch step + Skill-tool invocation,
grilling question wording rule, handoff names the OS temp dir, teach
workspace-path resolution + quiz answer-position rules, tdd seam notes.
find-skills (vercel-labs) and prototype already current. Skill updates
take effect next session (discovery runs at startup).

agent/skills/tdd/SKILL.md

@@ -7,7 +7,7 @@ description: Test-driven development. Use when the user wants to build features
 
 TDD is the red → green loop. This skill is the reference that makes that loop produce tests worth keeping: what a good test is, where tests go, the anti-patterns, and the rules of the loop. Every section applies on every cycle: consult them before and during the loop, not after.
 
-When exploring the codebase, read `CONTEXT.md` (if it exists) so test names and interface vocabulary match the project's domain language, and respect ADRs in the area you're touching.
+When exploring the codebase, read `GLOSSARY.md` (if it exists) so test names and interface vocabulary match the project's domain language, and respect ADRs in the area you're touching.
 
 ## What a good test is
 
@@ -21,7 +21,7 @@ A **seam** is the public boundary you test at: the interface where you observe b
 
 **Test only at pre-agreed seams.** Before writing any test, write down the seams under test and confirm them with the user. No test is written at an unconfirmed seam. You can't test everything, so agreeing the seams up front is how testing effort lands on the critical paths and complex logic instead of every edge case.
 
-Ask: "What's the public interface, and which seams should we test?"
+Ask: "What's the public interface, and which seams should we test?" Give each proposed seam a one-line note on what it catches and what it misses.
 
 When the shape of that interface is itself in question (how deep the module is, where the seam belongs, what the interface should expose), call the Skill tool with "codebase-design" for the vocabulary. It is the shared source of the module, interface, depth, seam, adapter, leverage and locality terms, and it is a reference to consult, not a session to run.