feat: 新增 S3 兼容云存储同步 (#1351)

* Add S3 Cloud Sync design document

Design for adding AWS S3 as a new Cloud Sync backend alongside WebDAV.
Hybrid approach: extract shared sync protocol, add independent S3 transport.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Add S3 cloud sync implementation design (reqwest + Sig V4)

Updated design based on 2026-03-06 draft: switches from rust-s3 crate
to hand-rolled AWS Sig V4 on existing reqwest for broader S3-compatible
service support (AWS, MinIO, R2, Alibaba OSS, Tencent COS, Huawei OBS).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Add S3 cloud sync implementation plan (11 tasks, TDD)

Detailed step-by-step plan covering: sync_protocol extraction, S3 Sig V4
transport, settings, sync/auto-sync modules, Tauri commands, frontend
presets/dynamic form, and i18n.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* deps: add hmac crate for S3 Sig V4 signing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* refactor: extract sync_protocol.rs from webdav_sync.rs for shared use

Move transport-agnostic sync protocol logic (constants, types, snapshot
building, manifest validation, artifact verification, snapshot application,
utilities) into a new shared sync_protocol module so both WebDAV and the
upcoming S3 transport can reuse it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: use transport-neutral error keys in sync_protocol

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 transport layer with AWS Sig V4 signing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3SyncSettings to AppSettings

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 sync module with upload/download/fetch

Implements the S3 sync protocol layer (s3_sync.rs) that combines the
shared sync_protocol with the S3 transport. Mirrors the WebDAV sync
module structure with independent sync mutex, connection check,
upload, download, fetch_remote_info, and sync status persistence.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 auto sync worker with debounce

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 sync Tauri commands and auto sync worker startup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 sync TypeScript types and API layer

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 sync i18n translations (en/zh/ja)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: add S3 sync presets and dynamic form to sync settings

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: preserve HTTP scheme for S3 custom endpoints (MinIO support)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* test: add live S3 integration tests (env-var driven, --ignored)

Run with: S3_TEST_AK=... S3_TEST_SK=... S3_TEST_BUCKET=... cargo test --lib services::s3::integration_tests -- --ignored

Verifies test_connection, put_object, get_object, head_object, and 404
handling against a real S3 bucket using the project's own Sig V4 signing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore: remove internal design docs before PR

* fix: wire S3 auto-sync to DB hook & sync UI state on async load

- P1: Add s3_auto_sync::notify_db_changed call in SQLite update_hook
  so S3 auto-sync worker receives DB change signals (was only wired
  for WebDAV, leaving S3 worker idle)

- P2: Add useEffect to update syncType selector when s3Config loads
  asynchronously, preventing stale "webdav" default for S3 users

* fix: satisfy clippy for s3 sync

* fix: address s3 sync review feedback

---------

Co-authored-by: Keith (via OpenClaw) <keithyt06@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Jason <farion1231@gmail.com>

src-tauri/src/services/webdav_sync/archive.rs

@@ -10,19 +10,21 @@ use zip::DateTime;
 use crate::error::AppError;
 use crate::services::skill::SkillService;
 
-use super::{io_context_localized, localized, MAX_SYNC_ARTIFACT_BYTES, REMOTE_SKILLS_ZIP};
+use crate::services::sync_protocol::{
+    io_context_localized, localized, MAX_SYNC_ARTIFACT_BYTES, REMOTE_SKILLS_ZIP,
+};
 
 /// Maximum number of entries allowed in a zip archive.
 const MAX_EXTRACT_ENTRIES: usize = 10_000;
 
-pub(super) struct SkillsBackup {
+pub(crate) struct SkillsBackup {
     _tmp: TempDir,
     backup_dir: PathBuf,
     ssot_path: PathBuf,
     existed: bool,
 }
 
-pub(super) fn zip_skills_ssot(dest_path: &Path) -> Result<(), AppError> {
+pub(crate) fn zip_skills_ssot(dest_path: &Path) -> Result<(), AppError> {
     let source = SkillService::get_ssot_dir().map_err(|e| {
         localized(
             "webdav.sync.skills_ssot_dir_failed",
@@ -63,7 +65,7 @@ pub(super) fn zip_skills_ssot(dest_path: &Path) -> Result<(), AppError> {
     Ok(())
 }
 
-pub(super) fn restore_skills_zip(raw: &[u8]) -> Result<(), AppError> {
+pub(crate) fn restore_skills_zip(raw: &[u8]) -> Result<(), AppError> {
     let tmp = tempdir().map_err(|e| {
         io_context_localized(
             "webdav.sync.skills_extract_tmpdir_failed",
@@ -159,7 +161,7 @@ pub(super) fn restore_skills_zip(raw: &[u8]) -> Result<(), AppError> {
     Ok(())
 }
 
-pub(super) fn backup_current_skills() -> Result<SkillsBackup, AppError> {
+pub(crate) fn backup_current_skills() -> Result<SkillsBackup, AppError> {
     let ssot = SkillService::get_ssot_dir().map_err(|e| {
         localized(
             "webdav.sync.skills_ssot_dir_failed",
@@ -190,7 +192,7 @@ pub(super) fn backup_current_skills() -> Result<SkillsBackup, AppError> {
     })
 }
 
-pub(super) fn restore_skills_from_backup(backup: &SkillsBackup) -> Result<(), AppError> {
+pub(crate) fn restore_skills_from_backup(backup: &SkillsBackup) -> Result<(), AppError> {
     if backup.ssot_path.exists() {
         fs::remove_dir_all(&backup.ssot_path).map_err(|e| AppError::io(&backup.ssot_path, e))?;
     }