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/proxy/mod.rs

@@ -3,6 +3,7 @@
 //! 提供本地HTTP代理服务，支持多Provider故障转移和请求透传
 
 pub mod body_filter;
+pub mod cache_injector;
 pub mod circuit_breaker;
 pub mod error;
 pub mod error_mapper;
@@ -22,6 +23,7 @@ pub mod response_processor;
 pub(crate) mod server;
 pub mod session;
 pub mod thinking_budget_rectifier;
+pub mod thinking_optimizer;
 pub mod thinking_rectifier;
 pub(crate) mod types;
 pub mod usage;