What this PR does

This PR keeps daemon-to-ACP telemetry stitched through prompt dispatch by deriving the ACP prompt metadata traceparent from the active daemon bridge span instead of relying on the global outbound propagator. It also records the generated prompt id on the active daemon HTTP request span and stamps deferred blocked-on-user and hook spans with the owning session id resolved from their logical parent context.

The regression coverage exercises the daemon trace metadata injection path, the bridge prompt dispatch span ordering, the daemon prompt id span attribute, and the multi-session session attribution cases for deferred spans.

Why it's needed

qwen serve installs a no-op outbound propagator by default, so using propagation.inject() for daemon-to-ACP prompt metadata could leave the ACP child interaction without a usable parent traceparent. The daemon HTTP span also generated a promptId without attaching it to the current request span, and some deferred spans could fall back to a stale process-global session id in multi-session daemon scenarios. Together these gaps made the daemon HTTP span → bridge span → ACP child interaction span chain harder to reconstruct in OTel backends.

Reviewer Test Plan

How to verify

Run cd packages/core && npx vitest run src/telemetry/daemon-tracing.test.ts src/telemetry/session-tracing.test.ts and expect 130 passing tests.

Run cd packages/acp-bridge && npx vitest run src/bridge.test.ts and expect 251 passing tests.

Run cd packages/cli && npx vitest run src/serve/server.test.ts and expect 408 passing tests.

Run npx prettier --check packages/core/src/telemetry/daemon-tracing.ts packages/core/src/telemetry/daemon-tracing.test.ts packages/core/src/telemetry/session-tracing.ts packages/core/src/telemetry/session-tracing.test.ts packages/cli/src/serve/server.ts packages/cli/src/serve/server.test.ts packages/acp-bridge/src/bridge.test.ts and expect all matched files to use Prettier code style.

Run npm run build && npm run typecheck and expect exit code 0. Local output still includes existing VS Code companion curly lint warnings, Browserslist stale-data warnings, and the existing web-shell chunk-size warning.

Evidence (Before & After)

N/A

Tested on

Environment (optional)

Node.js v22.22.3, npm 10.9.8.

Risk & Scope

• Main risk or tradeoff: The daemon now synthesizes ACP prompt traceparent from the active span and continues stripping client-supplied reserved trace metadata; tracestate is not synthesized because this codebase has no internal tracestate source for this path.
• Not validated / out of scope: Windows and Linux were not run locally; CI should cover cross-platform behavior.
• Breaking changes / migration notes: None.

Linked Issues

Related to #4554.