refactor: content-addressed assets, cross-channel multimodal, infra simplification (#63)

* refactor(attachment): multimodal attachment refactor with snapshot schema and storage layer

- Add snapshot schema migration (0008) and update init/versions/snapshots
- Add internal/attachment and internal/channel normalize for unified attachment handling
- Move containerfs provider from internal/media to internal/storage
- Update agent types, channel adapters (Telegram/Feishu), inbound and handlers
- Add containerd snapshot lineage and local_channel tests
- Regenerate sqlc, swagger and SDK

* refactor(media): content-addressed asset system with unified naming

- Replace asset_id foreign key with content_hash as sole identifier
  for bot_history_message_assets (pure soft-link model)
- Remove mime, size_bytes, storage_key from DB; derive at read time
  via media.Resolve from actual storage
- Merge migrations 0008/0009 into single 0008; keep 0001 as canonical schema
- Add Docker initdb script for deterministic migration execution order
- Fix cross-channel real-time image display (Telegram → WebUI SSE)
- Fix message disappearing on refresh (null assets fallback)
- Fix file icon instead of image preview (mime derivation from storage)
- Unify AssetID → ContentHash naming across Go, Agent, and Frontend
- Change storage key prefix from 4-char to 2-char for directory sharding
- Add server-entrypoint.sh for Docker deployment migration handling

* refactor(infra): embedded migrations, Docker simplification, and config consolidation

- Embed SQL migrations into Go binary, removing shell-based migration scripts
- Consolidate config files into conf/ directory (app.example.toml, app.docker.toml, app.dev.toml)
- Simplify Docker setup: remove initdb.d scripts, streamline nginx config and entrypoint
- Remove legacy CLI, feishu-echo commands, and obsolete incremental migration files
- Update install script and docs to require sudo for one-click install
- Add mise tasks for dev environment orchestration

* chore: recover migrations

---------

Co-authored-by: Acbox <acbox0328@gmail.com>

README_CN.md

@@ -31,19 +31,21 @@ Memoh 是一个 AI Agent 系统平台。用户可通过 Telegram、Discord、飞
 一键安装（**需先安装 [Docker](https://www.docker.com/get-started/)**）：
 
 ```bash
-curl -fsSL https://raw.githubusercontent.com/memohai/Memoh/main/scripts/install.sh | sh
+curl -fsSL https://raw.githubusercontent.com/memohai/Memoh/main/scripts/install.sh | sudo sh
 ```
 
-*静默安装（全部默认）：`curl -fsSL ... | sh -s -- -y`*
+*静默安装（全部默认）：`curl -fsSL ... | sudo sh -s -- -y`*
 
 或手动部署：
 
 ```bash
 git clone --depth 1 https://github.com/memohai/Memoh.git
 cd Memoh
-docker compose up -d
+sudo docker compose up -d
 ```
 
+> macOS 或用户已在 `docker` 用户组中时，无需 `sudo`。
+
 启动后访问 <http://localhost:8082>。默认登录：`admin` / `admin123`
 
 自定义配置与生产部署请参阅 [DEPLOYMENT.md](DEPLOYMENT.md)。