refactor: restructure project layout and add install.mjs

- Move src/ → plugin/ with subdirectories:
  - plugin/core/ (business logic, models, store, permissions, utils, memory)
  - plugin/tools/ (query, resources)
  - plugin/commands/ (placeholder for slash commands)
  - plugin/hooks/ (placeholder for lifecycle hooks)
  - plugin/index.ts (wiring layer only, no business logic)
- Add install.mjs with --install, --uninstall, --openclaw-profile-path
- Add skills/ and docs/ root directories
- Move planning docs (PLAN.md, FEAT.md, AGENT_TASKS.md) to docs/
- Remove old scripts/install.sh
- Update tsconfig rootDir: src → plugin
- Update README.md and README.zh.md with new layout
- Bump version to 0.2.0
- All tests pass

plugin/core/config/defaults.ts

@@ -0,0 +1,18 @@
+import type { StoreState, YonexusSchema } from "../models/types";
+
+export const DEFAULT_STATE: StoreState = {
+  organizations: [],
+  departments: [],
+  teams: [],
+  agents: [],
+  identities: [],
+  supervisors: []
+};
+
+export const DEFAULT_SCHEMA: YonexusSchema = {
+  position: { type: "string", queryable: true },
+  discord_user_id: { type: "string", queryable: true },
+  git_user_name: { type: "string", queryable: true },
+  department: { type: "string", queryable: false },
+  team: { type: "string", queryable: false }
+};