feat(doctor): report skill plugins the pipelines name but nothing provides

The ship-feature pipelines have always depended on the `superpowers`
plugin — skills/ship-feature/SKILL.md calls its skills by name, and the
node detect rules match `Skill` events named `brainstorming`,
`writing-plans`, `test-driven-development` — but no README, INSTALL,
manifest or SKILL.md said so, and /ccam-doctor did not check. Install the
`ccam` plugin without it and `/ccam:ship-feature-lane` runs partway, then
fails at the first skill call with no warning beforehand.

/ccam-doctor now derives the requirement from the loaded pipeline
templates rather than a hardcoded list: every `/plugin:skill` a template
names, as its own `skill` or as one node's `command`, has to come from an
installed and enabled plugin. Editing a template cannot leave the check
behind, and a custom template in DASHBOARD_PIPELINES_DIR naming some
other plugin is covered for free.

Three deliberate calls:
  - WARN, never FAIL. The dashboard, hooks, CLI and MCP all work without
    it; failing a doctor run over it would cry wolf.
  - A plugin present but explicitly disabled counts as missing — Claude
    Code will not resolve its skills either way.
  - The skills sitting in ~/.claude/skills/ count as satisfied. That is a
    legitimate hand-copied setup, and calling it broken is how a warning
    row teaches its reader to ignore it.

Docs state the prerequisite where someone installing would look: README
and INSTALL requirements, plus docs/PLUGINS.md for how the row decides.
The install line is `superpowers@claude-plugins-official`, verified
present in that marketplace's manifest.

Verified: npm run test:server (1379, +6 covering all three calls above
plus the partially-satisfied case), npm run test:client (459), prettier
and check-headers clean. `node scripts/plugin-doctor.js` here reports
`OK Skill plugins superpowers available`; the WARN branches were checked
against a temp CLAUDE_HOME.

docs/PLUGINS.md

@@ -176,10 +176,29 @@ reboot, same as always.
 
 | Command | Does |
 |---|---|
-| `/ccam-doctor` | Node version, bootstrap state, runtime deps, server liveness, duplicate hooks, CLI launcher + PATH, MCP build freshness, UI bundle |
+| `/ccam-doctor` | Node version, bootstrap state, runtime deps, server liveness, duplicate hooks, CLI launcher + PATH, **skill plugins** (see below), MCP build freshness, UI bundle |
 | `/ccam-update` | Pull the latest `ccam` release via `claude plugin marketplace update` + `claude plugin update ccam@<marketplace> -y`, then reinstall dependencies and restart the server (`plugin-bootstrap.js --force`). The plugin pull needs a manual `/reload-plugins` afterward to take effect in the current session — not scriptable from a command. |
 | `/ccam-open` | Rebuild the UI bundle and print the dashboard URL. Re-runs the bootstrap first when the server is down or still executing a plugin root that a mid-session `/plugin` update retired, so a fresh bundle never talks to an older server's routes |
 
+#### The `Skill plugins` row
+
+Derived from the loaded pipeline templates, not hardcoded: every `/plugin:skill`
+string a template names — as the pipeline's own `skill` or as one node's
+`command` — has to come from an installed, enabled plugin. Today that means
+**`superpowers`**, which `/ccam:ship-feature` and `/ccam:ship-feature-lane`
+drive step by step (`brainstorming`, `writing-plans`,
+`test-driven-development`, `requesting-code-review`,
+`verification-before-completion`, `finishing-a-development-branch`). Install it
+with `claude plugin install superpowers@claude-plugins-official`.
+
+The row is a **WARN, never a FAIL**: the dashboard, hooks, CLI and MCP all work
+without it, and only those two pipeline skills stop partway. A plugin listed but
+explicitly disabled counts as missing — Claude Code will not resolve its skills.
+The skills present as plain user skills under `~/.claude/skills/` count as
+satisfied, so a hand-copied setup is not reported as broken. A custom template
+in `DASHBOARD_PIPELINES_DIR` naming some other plugin's command is checked the
+same way.
+
 ### Where things live
 
 | Thing | Location | Survives a plugin update |