t3-provision-users: vendor agent skills + per-user install_skills (emo)

Make the admin's Claude Code agent skills available to the `emo` devvm user.
Viktor asked to install Matt Pocock's skills for emo, starting with grill-me
but covering the full set the admin already uses.

The `npx skills` upstream has drifted off that set (diagnose -> diagnosing-bugs
and write-a-skill -> writing-great-skills were renamed; caveman + zoom-out are
no longer published), so reproducing it via npx is impossible and would also
spray ~70 agent dirs into the user's home + add a GitHub-clone + unpinned-CLI
dependency to the hourly root reconcile. Instead vendor a point-in-time
snapshot of the 16 skills (scripts/workstation/claude-skills/) and copy them
per-user, mirroring install_memory: install_skills() copies each skill into
~/.agents/skills/<name> (owned by the user) and symlinks
~/.claude/skills/<name> -> ../../.agents/skills/<name>. if-absent, additive,
best-effort, scoped to the SKILL_USERS allowlist (emo).

find-skills is from vercel-labs/skills (not Matt Pocock) but included since it
is part of the admin's current set.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/workstation/claude-skills/teach/RESOURCES-FORMAT.md

@@ -0,0 +1,32 @@
+# RESOURCES.md Format
+
+`RESOURCES.md` is the curated set of trusted sources for this topic. Knowledge for explainers should be drawn from here, not from parametric guesses. Wisdom comes from the communities listed here.
+
+## Structure
+
+```md
+# {Topic} Resources
+
+## Knowledge
+
+- [Book: _The Science and Practice of Strength Training_ — Zatsiorsky & Kraemer](https://example.com)
+  Foundational text on programming and adaptation. Use for: anything to do with periodisation, recovery, intensity zones.
+- [Article: "How Much Should I Train?" — Greg Nuckols (Stronger By Science)](https://example.com)
+  Evidence-based review of volume landmarks. Use for: weekly set targets per muscle group.
+
+## Wisdom (Communities)
+
+- [r/weightroom](https://reddit.com/r/weightroom)
+  High-signal subreddit, moderated against bro-science. Use for: programme critique, plateau troubleshooting.
+- Local: Tuesday strength class at {gym name}
+  Use for: real-time coaching feedback on lifts.
+```
+
+## Rules
+
+- **High-trust only.** Prefer primary sources, recognised experts, peer-reviewed work, and communities with strong moderation. If a resource is marketing dressed as education, leave it out.
+- **Annotate every entry.** A bare link is useless in three months. Add one line: what it covers and when to reach for it.
+- **Group by Knowledge / Wisdom.** Mirrors the philosophy in [SKILL.md](./SKILL.md). It is fine for a resource to appear in only one group.
+- **Surface gaps explicitly.** If no good resource exists for an area the mission needs, write a `## Gaps` section listing what is missing. This drives future search.
+- **Prune ruthlessly.** A resource that turned out to be wrong, shallow, or off-mission should be removed, not buried. Better five sharp sources than thirty mediocre ones.
+- **Record community preferences.** If the user has opted out of joining communities, note it here so future sessions don't keep proposing them.