chore(cymbal-resolution): wire image into deploy matrix

[hpouillot]

Problem

The cymbal-resolution service was not yet wired into the rust docker build deploy matrix, so the image was not being built and pushed for deploys.

Changes

• Add cymbal-resolution entry to the deploy matrix in .github/workflows/rust-docker-build.yml so the image is built and the chart digest is updated.
• Add a startup info! log of max_concurrent_requests in rust/cymbal-resolution/src/main.rs to make pod config observable and to bump the image build.

How did you test this code?

I'm an agent — no manual testing. Relying on CI to validate the workflow change and image build. Existing cymbal-resolution unit tests cover the binary; the added log line is a pure additive tracing::info! with no behavior change.

Publish to changelog?

no

🤖 Agent context

Authored with Claude Code (Opus 4.7). The user asked for a small change to cymbal-resolution to force a rebuild after wiring the service into the deploy matrix; we added a startup log line that also surfaces the configured concurrency limit, which is useful info to keep. Also did a quick audit of the logging surface at info level for prod noise — no per-request info logs on the resolve hot path. Flagged rust/cymbal/src/symbol_store/saving.rs symbol-fetch info logs as a separate, pre-existing noise concern for follow-up.

[github-actions]

Hey @hpouillot! 👋

It looks like your git author email on this PR isn't your @posthog.com address (hpouillot@gmail.com). Since you're on the PostHog team, it's worth pointing your local git author email at your @posthog.com address. Why it matters:

• Consistent work identity in git history — internal tooling that attributes commits to team members keys off your @posthog.com address.
• Keeps team contributions easy to tell apart from external community ones when scanning history.

You can fix it for this repo with:

git config user.email "you@posthog.com"

Or set it globally with git config --global user.email "you@posthog.com". No need to redo this PR — just a nudge for next time. 🙂

[greptile-apps]

_{Reviews (1): Last reviewed commit: "Merge branch 'master' into hp/cymbal-res..." | Re-trigger Greptile}

[github-actions]

Trivial additive log line, no risk.

New commits pushed (delta classified non_trivial_delta) — stamphog approval dismissed; re-review running automatically.

[github-actions]

Trivial additive log line, no risk.

[deployment-status-posthog]

Deploy status

Environment	Status	Deployed At	Workflow
dev	✅ Deployed	2026-06-01 14:14 UTC	Run
prod-us	✅ Deployed	2026-06-01 14:35 UTC	Run
prod-eu	✅ Deployed	2026-06-01 15:32 UTC	Run