chore: sync versions, update uv, expand dockerignore

- plugin.json: bump version 0.2.0 → 0.4.0 to match pyproject.toml
- Dockerfile: update uv 0.5.4 → 0.6 (global CLAUDE.md requires 0.10+)
- .dockerignore: exclude tests/, docs/, scripts/, commands/, .full-review/,
  .claude-plugin/, *.md (keep README.md) — reduces image size

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "unraid",
   "description": "Query and monitor Unraid servers via GraphQL API - array status, disk health, containers, VMs, system monitoring",
-  "version": "0.2.0",
+  "version": "0.4.0",
   "author": {
     "name": "jmagar",
     "email": "jmagar@users.noreply.github.com"