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/i18n/locales/en.json

@@ -257,6 +257,18 @@
         "thinkingBudget": "Thinking Budget Rectification",
         "thinkingBudgetDescription": "When an Anthropic-type provider returns budget_tokens constraint errors (such as at least 1024), automatically normalizes thinking to enabled, sets thinking budget to 32000, and raises max_tokens to 64000 if needed, then retries once"
       },
+      "optimizer": {
+        "title": "Bedrock Request Optimizer",
+        "description": "Automatically optimize Thinking and Cache configuration before sending requests (only applies to Bedrock providers)",
+        "enabled": "Enable Optimizer",
+        "thinkingOptimizer": "Thinking Optimization",
+        "thinkingOptimizerDescription": "Automatically enable Adaptive Thinking for Opus/Sonnet, and inject Extended Thinking for legacy models",
+        "cacheInjection": "Cache Injection",
+        "cacheInjectionDescription": "Automatically inject cache breakpoints at key positions in requests to reduce duplicate token billing",
+        "cacheTtl": "Cache TTL",
+        "cacheTtl5m": "5 minutes",
+        "cacheTtl1h": "1 hour"
+      },
       "logConfig": {
         "title": "Log Management",
         "description": "Control log output level",

src/i18n/locales/ja.json

@@ -257,6 +257,18 @@
         "thinkingBudget": "Thinking Budget 整流",
         "thinkingBudgetDescription": "Anthropic タイプのプロバイダーが budget_tokens 制約エラー（例: 1024 以上）を返した場合、thinking を enabled に正規化し、thinking 予算を 32000 に設定し、必要に応じて max_tokens を 64000 に引き上げて 1 回リトライします"
       },
+      "optimizer": {
+        "title": "Bedrock リクエストオプティマイザー",
+        "description": "リクエスト送信前に Thinking と Cache の設定を自動最適化（Bedrock プロバイダーのみ有効）",
+        "enabled": "オプティマイザーを有効化",
+        "thinkingOptimizer": "Thinking 最適化",
+        "thinkingOptimizerDescription": "Opus/Sonnet に Adaptive Thinking を自動的に有効化し、レガシーモデルに Extended Thinking を注入",
+        "cacheInjection": "Cache 注入",
+        "cacheInjectionDescription": "リクエストの重要な位置に Cache ブレークポイントを自動注入し、重複トークンの課金を削減",
+        "cacheTtl": "Cache TTL",
+        "cacheTtl5m": "5 分",
+        "cacheTtl1h": "1 時間"
+      },
       "logConfig": {
         "title": "ログ管理",
         "description": "ログ出力レベルを制御",

src/i18n/locales/zh.json

@@ -257,6 +257,18 @@
         "thinkingBudget": "Thinking Budget 整流",
         "thinkingBudgetDescription": "当 Anthropic 类型供应商返回 budget_tokens 约束错误（如至少 1024）时，自动将 thinking 规范为 enabled 并将 budget 设为 32000，同时在需要时将 max_tokens 设为 64000，然后重试一次"
       },
+      "optimizer": {
+        "title": "Bedrock 请求优化器",
+        "description": "在请求发送前自动优化 Thinking 和 Cache 配置（仅 Bedrock 供应商生效）",
+        "enabled": "启用优化器",
+        "thinkingOptimizer": "Thinking 优化",
+        "thinkingOptimizerDescription": "自动为 Opus/Sonnet 启用 Adaptive Thinking，为旧模型注入 Extended Thinking",
+        "cacheInjection": "Cache 注入",
+        "cacheInjectionDescription": "自动在请求关键位置注入 Cache 断点，减少重复 token 计费",
+        "cacheTtl": "Cache TTL",
+        "cacheTtl5m": "5 分钟",
+        "cacheTtl1h": "1 小时"
+      },
       "logConfig": {
         "title": "日志管理",
         "description": "控制日志输出级别",