feat: 品牌替换 + 启动优化 + AGENTS.md 模板定制

- 品牌替换：OpenCode/opencode → AirCoding/aircoding（16+ 文件）
- Logo ASCII art：修复 left/right 行数不匹配导致的启动崩溃
- 启动诊断：添加 OPENCODE_PRINT_TIMING 计时探针
- dev 模式默认 --pure 跳过外部插件加载
- AGENTS.md 模板：追加 AirCoding 多 Agent 专项段落
- architect prompt + plugin：强化 AGENTS.md 产出验证

packages/core/migration/20260228203230_blue_harpoon/migration.sql

@@ -0,0 +1,17 @@
+CREATE TABLE `account` (
+	`id` text PRIMARY KEY,
+	`email` text NOT NULL,
+	`url` text NOT NULL,
+	`access_token` text NOT NULL,
+	`refresh_token` text NOT NULL,
+	`token_expiry` integer,
+	`selected_org_id` text,
+	`time_created` integer NOT NULL,
+	`time_updated` integer NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE `account_state` (
+	`id` integer PRIMARY KEY NOT NULL,
+	`active_account_id` text,
+	FOREIGN KEY (`active_account_id`) REFERENCES `account`(`id`) ON UPDATE no action ON DELETE set null
+);