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/store/auditStore.ts

@@ -0,0 +1,19 @@
+import type { AuditLogEntry } from '../models/audit';
+
+const MAX_AUDIT = 1000;
+
+export class AuditStore {
+  private logs: AuditLogEntry[] = [];
+
+  append(entry: AuditLogEntry): AuditLogEntry {
+    this.logs.push(entry);
+    if (this.logs.length > MAX_AUDIT) this.logs.shift();
+    return entry;
+  }
+
+  list(limit = 100, offset = 0): AuditLogEntry[] {
+    const safeLimit = Math.min(Math.max(1, limit), 500);
+    const safeOffset = Math.max(0, offset);
+    return this.logs.slice(safeOffset, safeOffset + safeLimit);
+  }
+}