fix(just): install plugins at user scope; fail loudly on unresolved slash commands

[laurigates]

Problem

just -g plugins-setup-repo still failed after #352:

Configuring Claude plugins for repository at .../podio-mcp...
Unknown command: /configure-claude-plugins

…and the recipe reported success anyway.

Root cause: install scope, not command name

All 40 marketplace plugins were installed at project scope, bound to
~/repos/ForumViriumHelsinki/thelma — the cwd of a plugins-install run on
2026-03-08. A project-scoped plugin's skills load only when cwd is that
project, so /configure-claude-plugins resolved in no other repo.

The failure was invisible because both status signals report enablement, not
reachability:

Signal	Says	Actually means
enabledPlugins in settings.json	true	user wants it on
claude plugin list	Status: ✔ enabled	it is not disabled
claude plugin list --json → .scope	project	loads only in one directory

Confirmed empirically: the only plugin skills that loaded in any session were
session-plugin and comfyui-plugin — exactly the two records with
"scope": "user" in installed_plugins.json. Installing configure-plugin
with --scope user made /configure-claude-plugins resolve immediately.

#352 fixed the slash-command names (a real, separate bug). It verified them
against the marketplace inventory rather than by resolving them, so this layer
stayed hidden.

Changes

• plugins-install passes --scope user. It is today's CLI default, but
  explicit means a future run from inside a repo can't silently re-scope the
  whole set again.
• New plugins-install-audit — flags any marketplace plugin with no
  user-scope install record; exits 1 so it can gate.
• New private _claude-slash — one call site for every headless
  claude -p "/<skill>". claude -p prints Unknown command: /foo and
  exits 0, so the old exit-code check reported ok while nothing ran. The
  guard greps the output and converts that to rc=3 with the fix instructions.
  Used by plugins-setup-repo, plugins-check-repo, and plugins-bulk.
• _claude-slash cds into the target repo. Separate pre-existing bug:
  plugins-bulk ran every picked repo's claude call from the invocation cwd,
  so an N-repo selection configured the launch directory N times instead of
  each repo once.

Verification

• just -g plugins-install-audit: 39 project-scoped-only before, clean
  (exit 0) after just -g plugins-install.
• just -g plugins-check-repo in podio-mcp — previously Unknown command +
  exit 0 — now runs the skill to completion and returns a real report.
• just -g --list parses; both new recipes render correct descriptions.
• pre-commit run check-justfiles passes on the changed file.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Ne1Yce6SxwJLknhroAfPVB

[github-actions]

🤖 Claude analyzed the CI failures but determined no code changes are needed.

Failed workflow: https://github.com/laurigates/dotfiles/actions/runs/31080743939

This may indicate:

• Flaky tests
• Infrastructure issues
• Transient failures
• Configuration problems outside the codebase

Please review the failure logs manually.