perf: reduce redundant tokens sent per turn for Codex and Claude providers

[ccbq2010]

Summary

• P0-4: Remove "local" from CLAUDE_SETTING_SOURCES so Claude sessions no longer load CLAUDE.local.md on every session start
• P0-3: Skip setPermissionMode call when the permission mode hasn't changed between turns (unnecessary SDK round-trip per turn)
• P0-1 / P1 / P2: Add lastSentTurnParams diff mechanism to CodexAppServerManager — collaborationMode (developer_instructions), approvalPolicy/sandboxPolicy, model, and effort are only sent when they change or on the first turn after a thread open

Background

Codex app-server persists collaborationMode, approvalPolicy, sandboxPolicy, model, and effort across turns on the same thread. PeakCode was re-sending all of these on every turn/start, wasting tokens each turn.

Root cause: interactionMode and runtimeMode in ThreadTurnStartRequestedPayload have Schema.withDecodingDefault, so they are never undefined — all conditional "only send if changed" guards were dead code.

Token savings per turn

Field	Default mode	Plan mode
collaborationMode / developer_instructions	~504 tokens	~2,255 tokens
approvalPolicy + sandboxPolicy	~19 tokens	~19 tokens
model + effort	~10 tokens	~10 tokens

Changes

• apps/server/src/codexAppServerManager.ts — CodexLastSentTurnParams type + lastSentTurnParams field on context; reset on thread/start / thread/resume; diff in sendTurn
• apps/server/src/codexAppServerManager.test.ts — 4 new deduplication tests
• apps/server/src/provider/Layers/ClaudeAdapter.ts — lastSentPermissionMode field on context; conditional setPermissionMode; remove "local" from CLAUDE_SETTING_SOURCES
• apps/server/src/provider/Layers/ClaudeAdapter.test.ts — update 2 test assertions for new settingSources value

Test plan

• First turn after thread open sends all fields (collaborationMode, approvalPolicy, sandboxPolicy, model, effort)
• Subsequent turns with unchanged params omit all deduped fields
• interactionMode change re-sends collaborationMode with correct mode
• runtimeMode change re-sends approvalPolicy / sandboxPolicy
• bun fmt && bun lint && bun typecheck all pass