fix(pb-envoy): reduce round trips for ws connection

[MasterPtato]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

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• I have performed a self-review of my code
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• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[MasterPtato]

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• fix(epoxy): add list operation #4604
• fix(pb-envoy): reduce round trips for ws connection #4603 👈 (View in Graphite)
• fix(envoy-client): fix handling actor event ack #4599
• DO NOT MERGE: sandbox benches #4597 : 1 other dependent PR (#4600 )
• fix(envoy-client): add tls #4595
• chore: fix driver test suite #4591
• chore: tunnel auth #4588
• chore: remove udb as a dependency of envoy-client #4587
• chore: revert actor v2 hack #4586
• fix: fix pool metadata protocol version refresh, rivetkit native ws #4585
• feat: US-001 - Define SqliteKv trait in rivetkit-sqlite-native #4584
• feat(rust/engine-runner): minimal rust engine runner #4289
• chore: delete kv channel #4583
• feat(engine): rust runner #4582
• chore: remove non-engine drivers #4574 : 1 other dependent PR (#4581 )
• feat: dynamic actors #4397
• fix: driver test suite & sqlite reliability #4559
• fix: remove serverless token #4572
• fix: misc token fixes #4569
• fix(pb): clean up actor stop decision handling #4566
• fix(envoy): use global instance, add signal handlers #4565
• chore: misc fixes, add pb snapshot test #4561
• fix(cache): make in memory cache global #4560
• main

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[claude]

The core optimization is solid. Moving the version to the URL query param and having the server immediately push the init packet instead of waiting for a client round trip is a clean improvement.

Critical Bug: is_serverless always false in Conn

In engine/packages/pegboard-envoy/src/conn.rs, Arc::new(Conn) at the end of init_conn hardcodes is_serverless: false (line 326) instead of the computed local variable from tokio::try_join. Two places are affected:

• ping_task.rs:43: update_lb is always true for serverless (should be false)
• ws_to_tunnel_task.rs:390: serverless connections incorrectly call expire on ToRivetStopping

Fix: change is_serverless: false to is_serverless in the struct literal.

Units inconsistency: drain_grace_period

The deprecated serverless_drain_grace_period config is in milliseconds (default 10,000 ms = 10 s). The new drain_grace_period field is documented as Seconds but uses the same raw value 10,000. If truly seconds that is ~2.7 hours. The Seconds doc comment is likely wrong and should say Milliseconds.

Default fallback does not read the actual deprecated config value

The comment says Default to deprecated config value but the code hardcodes 10,000 rather than reading config.pegboard.serverless_drain_grace_period. A non-default operator value will be silently ignored.

Missing newline at end of file

engine/artifacts/errors/ws.timed_out.json is missing a trailing newline.

Old error artifact files not removed

WsError::ConnectionClosed and WsError::TimedOutWaitingForInit were removed from errors.rs but ws.connection_closed.json and ws.timed_out_waiting_for_init.json were not deleted.

Unrelated changes in examples/cursors/package.json

Adds @hono/node-server and hono deps and removes trailing newline. Should be a separate PR.

Minor: handle_metadata allows repeated updates

Previously written once at init; now runs on every ToRivetMetadata message. Atomicity is fine. Worth a comment confirming this is intentional.

Summary: The is_serverless: false bug and the drain_grace_period units issue are the two things that need to be fixed before landing.