feat(plugins): make CCAM installable straight from a Claude Code plugin

Adds a root `ccam` plugin (`.claude-plugin/plugin.json`, `"source": "./"`) so
`/plugin marketplace add` + `/plugin install ccam@...` is enough on a machine
with nothing but Claude Code: no clone, no npm run setup, no manual npm start.

- scripts/plugin-bootstrap.js: SessionStart hook. Fast-path exit, Node >=22.5
  gate (node:sqlite), mkdir lock with stale reclaim, deps installed into
  ~/.claude/agent-dashboard/runtime/ (never the plugin cache), legacy
  checkout-hook cleanup (backed up), ~/.local/bin/ccam launcher, eager UI
  build so client routes like /run work immediately, detached server spawn.
- scripts/plugin-open.js, scripts/plugin-doctor.js: /ccam-open, /ccam-doctor.
- server/index.js: DASHBOARD_CLIENT_DIST override (plugin cache is read-only).
- mcp/build/ is committed (plugin MCP servers start before any bootstrap could
  build them) and kept honest by scripts/check-mcp-build.js (content hash,
  not mtime), enforced by pre-commit when mcp/src changes.
- plugins/ccam-dashboard/.mcp.json moved under plugins/ccam/ with a working
  ${CLAUDE_PLUGIN_ROOT} path (the old relative path never resolved from a
  marketplace-cached subdir).
- Docs: README, INSTALL, SETUP, ARCHITECTURE, CLAUDE.md, docs/PLUGINS.md,
  docs/MCP.md, docs/CLI.md, docs/HOOKS.md.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

plugins/ccam-dashboard/.mcp.json

@@ -1,11 +0,0 @@
-{
-  "mcpServers": {
-    "ccam-dashboard": {
-      "command": "node",
-      "args": ["../../mcp/build/index.js"],
-      "env": {
-        "CCAM_DASHBOARD_URL": "http://localhost:4820"
-      }
-    }
-  }
-}

plugins/ccam-dashboard/agents/dashboard-operator.md

@@ -22,10 +22,12 @@ keep the dashboard running and observable. You query the dashboard API at
 data-backed output, and you guide the user through starting, restarting, and
 feeding data into the dashboard.
 
-This plugin also ships a bundled MCP server (`ccam-dashboard`, configured in
-`.mcp.json` against `CCAM_DASHBOARD_URL=http://localhost:4820`). When the MCP
-server is connected, you have direct tool access to the same dashboard
-operations — mention this to the user as a faster alternative to raw `curl`.
+The MCP server (`ccam`, pointed at `CCAM_DASHBOARD_URL=http://localhost:4820`)
+ships with the root `ccam` plugin, not with this one — a marketplace subdirectory
+plugin is cached without `mcp/`, so it cannot carry the server binary. When that
+plugin is installed and the MCP server is connected, you have direct tool access
+to the same dashboard operations — mention it to the user as a faster
+alternative to raw `curl`.
 
 ## Available Data Sources