feat: Add composite index for dependency queries

- Add idx_dependencies_depends_on_type index on (depends_on_id, type)
- Optimize queries filtering by both target issue and dependency type
- Improve performance for dep tree and relationship queries
- Update plugin version to 0.9.5
- Sync issue database

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

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

.claude-plugin/plugin.json

@@ -26,7 +26,8 @@
         "beads-mcp"
       ],
       "env": {
-        "BEADS_ACTOR": "${USER}"
+        "BEADS_ACTOR": "${USER}",
+        "BEADS_WORKING_DIR": "${PWD}"
       }
     }
   }