feat: add Bedrock request optimizer (PRE-SEND thinking + cache injection) (#1301)

* feat: add Bedrock request optimizer (PRE-SEND thinking + cache injection)

Add a PRE-SEND request optimizer that enhances Bedrock API requests
before forwarding, complementing the existing POST-ERROR rectifier system.

New modules:
- thinking_optimizer: 3-path model detection (adaptive/legacy/skip)
  - Opus 4.6/Sonnet 4.6: adaptive thinking + effort max + 1M context beta
  - Legacy models: inject extended thinking with max budget
  - Haiku: skip (no modification)
- cache_injector: auto-inject cache_control breakpoints (max 4)
  - Injects at tools/system/assistant message positions
  - TTL upgrade for existing breakpoints (5m → 1h)

Gate: only activates for Bedrock providers (CLAUDE_CODE_USE_BEDROCK=1)
Config: stored in SQLite settings table, default OFF, user opt-in
UI: new Optimizer section in RectifierConfigPanel with 3 toggles + TTL

18 unit tests covering all paths. Verified against live Bedrock API.

* chore: remove docs/plans directory

* fix: address code review findings for Bedrock request optimizer

P0 fixes:
- Replace hardcoded Chinese with i18n t() calls in optimizer panel,
  add translation keys to zh/en/ja locale files
- Fix u64 underflow: max_tokens - 1 → max_tokens.saturating_sub(1)
- Move optimizer from before retry loop to per-provider with body
  cloning, preventing Bedrock fields leaking to non-Bedrock providers

P1 fixes:
- Replace .map() side-effect pattern with idiomatic if-let (clippy)
- Fix module alphabetical ordering in mod.rs
- Add cache_ttl whitelist validation in set_optimizer_config
- Remove #[allow(unused_assignments)] and dead budget decrement

---------

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

src-tauri/src/commands/settings.rs

@@ -145,6 +145,36 @@ pub async fn set_rectifier_config(
     Ok(true)
 }
 
+/// 获取优化器配置
+#[tauri::command]
+pub async fn get_optimizer_config(
+    state: tauri::State<'_, crate::AppState>,
+) -> Result<crate::proxy::types::OptimizerConfig, String> {
+    state.db.get_optimizer_config().map_err(|e| e.to_string())
+}
+
+/// 设置优化器配置
+#[tauri::command]
+pub async fn set_optimizer_config(
+    state: tauri::State<'_, crate::AppState>,
+    config: crate::proxy::types::OptimizerConfig,
+) -> Result<bool, String> {
+    // Validate cache_ttl: only allow known values
+    match config.cache_ttl.as_str() {
+        "5m" | "1h" => {}
+        other => {
+            return Err(format!(
+                "Invalid cache_ttl value: '{other}'. Allowed values: '5m', '1h'"
+            ))
+        }
+    }
+    state
+        .db
+        .set_optimizer_config(&config)
+        .map_err(|e| e.to_string())?;
+    Ok(true)
+}
+
 /// 获取日志配置
 #[tauri::command]
 pub async fn get_log_config(