fix: Sync all component versions to 0.9.2

Fixes version inconsistencies across the project. All components now at 0.9.2:

Updated:
- .claude-plugin/plugin.json: 0.9.0 → 0.9.2
- .claude-plugin/marketplace.json: 0.9.0 → 0.9.2
- integrations/beads-mcp/pyproject.toml: 1.0.0 → 0.9.2
- README.md: v0.9.0 → v0.9.2
- PLUGIN.md: Updated version requirements

Root cause: Previous version bumps (0.9.0 → 0.9.1 → 0.9.2) only updated
cmd/bd/version.go, leaving other components out of sync.

The MCP server was initially versioned at 1.0.0 when added today, but
syncing to 0.9.2 for consistency since the project is still in alpha.

Closes bd-66

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

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

README.md

@@ -936,7 +936,7 @@ See [examples/](examples/) for scripting patterns. Contributions welcome!
 
 ### Is this production-ready?
 
-**Current status: Alpha (v0.9.0)**
+**Current status: Alpha (v0.9.2)**
 
 bd is in active development and being dogfooded on real projects. The core functionality (create, update, dependencies, ready work, collision resolution) is stable and well-tested. However: