feat: 模块统一 ias- 前缀、独立版本与内网地址支持 (0.1.7)

- 所有 Rust crate 统一加 ias- 前缀：ai → ias-ai、common → ias-common、context → ias-context、mail → ias-mail、service → ias-service、wechat → ias-wechat
- 新增 ias-main 模块承载 CLI 入口和二进制打包
- 各模块开始独立维护版本号，ias-main 0.1.7 代表整体版本
- 新增 IA_WEB_INTERNAL_URL 环境变量，版本通知同时发送公网和内网链接
- 将已有升级日志翻译为中文
- ias_upgrade_logs 新增 modules JSONB 字段
- 新增 VERSION 文件和 CHANGELOG.md
- 新增 AGENTS.md 项目规则文件

ias-service/migrations/20260706015000_mail_polling.sql

@@ -0,0 +1,48 @@
+CREATE TABLE ias_mail_messages (
+    id BIGSERIAL PRIMARY KEY,
+    source_key VARCHAR(512) NOT NULL,
+    mailbox VARCHAR(255) NOT NULL,
+    uid VARCHAR(255) NOT NULL,
+    message_id TEXT,
+    from_label TEXT NOT NULL DEFAULT '',
+    subject TEXT NOT NULL DEFAULT '',
+    summary TEXT NOT NULL DEFAULT '',
+    content_preview TEXT NOT NULL DEFAULT '',
+    preview_page_id BIGINT REFERENCES ias_web_pages(id) ON DELETE SET NULL,
+    preview_url TEXT,
+    received_at TIMESTAMPTZ,
+    raw_size BIGINT NOT NULL DEFAULT 0,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (source_key, mailbox, uid)
+);
+
+CREATE INDEX idx_ias_mail_messages_created
+    ON ias_mail_messages(created_at DESC);
+
+CREATE INDEX idx_ias_mail_messages_received
+    ON ias_mail_messages(received_at DESC);
+
+INSERT INTO ias_upgrade_logs (
+    version,
+    released_at,
+    title,
+    description,
+    changes
+) VALUES (
+    '0.1.4',
+    '2026-07-06T00:00:00+08:00',
+    'Mail polling and standalone HTTP module',
+    'Added a standalone mail module for IMAP polling and notifications, moved HTTP serving and web preview pages into a standalone Rust module, and added mail persistence tables.',
+    '[
+        "Added the standalone Rust mail module for IMAP mailbox polling, message parsing, database deduplication, preview-page creation, and user notifications.",
+        "Added the standalone Rust ias-http module for HTTP serving, health checks, and reusable web preview pages.",
+        "Moved the existing web preview routes out of service and into ias-http.",
+        "Added /mail-api/messages and /mail-api/messages/{id} for inspecting stored mail records.",
+        "Added the ias_mail_messages database table and persisted the 0.1.4 upgrade record.",
+        "Added mail polling configuration through IA_MAIL_* environment variables; polling stays disabled when mailbox settings are absent."
+    ]'::jsonb
+) ON CONFLICT (version) DO UPDATE SET
+    released_at = EXCLUDED.released_at,
+    title = EXCLUDED.title,
+    description = EXCLUDED.description,
+    changes = EXCLUDED.changes;