feat: add state store with JSON persistence

src/state/store.ts

@@ -0,0 +1,51 @@
+import { existsSync, mkdirSync, readFileSync, writeFileSync } from "fs";
+import { homedir } from "os";
+import { join } from "path";
+
+export interface SessionInfo {
+  sessionId: string;
+  cwd: string;
+  status: "idle" | "busy";
+}
+
+export interface AppState {
+  projects: Record<string, string>;
+  sessions: Record<string, SessionInfo>;
+  activeSession: string | null;
+}
+
+const STATE_DIR = join(homedir(), ".claude-telegram-bot");
+const STATE_FILE = join(STATE_DIR, "state.json");
+
+const DEFAULT_STATE: AppState = {
+  projects: {},
+  sessions: {},
+  activeSession: null,
+};
+
+export class Store {
+  private state: AppState;
+
+  constructor() {
+    this.state = this.load();
+  }
+
+  private load(): AppState {
+    if (!existsSync(STATE_FILE)) {
+      return { ...DEFAULT_STATE, projects: {}, sessions: {} };
+    }
+    const raw = readFileSync(STATE_FILE, "utf-8");
+    return JSON.parse(raw) as AppState;
+  }
+
+  save(): void {
+    if (!existsSync(STATE_DIR)) {
+      mkdirSync(STATE_DIR, { recursive: true });
+    }
+    writeFileSync(STATE_FILE, JSON.stringify(this.state, null, 2));
+  }
+
+  get data(): AppState {
+    return this.state;
+  }
+}