Scope compaction outcome parsing to OMP

[ymichael]

Human comments

What was wrong

The ACP bridge classified every successful manual-compaction response by looking for OMP-specific phrases such as compaction failed. That policy leaked across dialects, so a generic ACP or OpenCode response describing an earlier failed attempt could be reported as a failed compaction even when the agent's final result was successful.

What changed

• Move end-turn compaction classification into the ACP dialect contract.
• Apply the existing failure/no-op prose handling only to OMP.
• Let generic ACP and OpenCode keep the completed result reported by their successful end turn.
• Add regressions for generic ACP and OpenCode while preserving OMP failed and skipped outcomes.
• No wire contract or host-daemon protocol change is required.

How you verified

• pnpm exec turbo run test typecheck --filter=@bb/provider-bridge-acp --force (307 tests passed)
• pnpm exec turbo run test --filter=@bb/server --force -- "test/public/public-thread-compaction.test.ts" (4 tests passed)
• pnpm exec turbo run build:types --filter=@get-bb/plugin-sdk --force
• pnpm exec turbo run test --filter=@bb/plugin-api-map --force (75 tests passed; public SDK inventory unchanged)
• pnpm exec oxfmt --check packages/provider-bridge-acp/src/bridge/bridge.ts packages/provider-bridge-acp/src/bridge/bridge.test.ts packages/provider-bridge-acp/src/dialect.ts
• git diff --check origin/main...HEAD

Follow-up to #2293.

AGENT GENERATED