feat(railway): set Service CPU and memory limits - #2203

Railway.Service can now declare per-replica resource limits, the dashboard's Resource Limits setting.

const api = yield* Railway.Service("Api", {
  project,
  image: "ghcr.io/acme/api:latest",
  limits: { cpu: 1, memoryBytes: 4_000_000_000 },
});
api.limits; // { cpu: 1, memoryBytes: 4000000000 }

• Reconcile writes services[id].deploy.limitOverride.containers with environmentPatchCommit under withEnvironmentConfigLock, the same path region uses. It patches only the fields that differ, then waits until the config reflects them (bounded, failing with ServiceLimitsNotApplied).
• Omitting limits leaves the current limits untouched, and omitting a field keeps that field's value.
• The patch commit redeploys the service by itself, so reconcile does not add a deploy. I checked this against a live service.
• read reports the observed value as the new limits attribute. ServiceRegion.ts now exports its readEnvironmentConfig and environmentPatchCommit helpers so both modules share them.

Testing

• test/Railway/ServiceLimits.test.ts covers the pure helpers: reading the override, patching only differing fields, and leaving matching limits alone. It passes, as does ServiceRegion.test.ts.
• New live test in Service.test.ts: set a service's resource limits and change them. Create ({ cpu: 1, memoryBytes: 1e9 }) and update ({ memoryBytes: 2e9 }, keeping cpu: 1) passed their assertions, the environment config showed the new override, and the deployment reached SUCCESS. The final stack.destroy() failed with Not Authorized, because the account I tested with can't run serviceDelete (see Railway.Service delete removes the service from every environment #2179), so cleanup still needs a run with delete rights.
• tsc -b packages/alchemy/tsconfig.json, which builds the referenced distilled projects first, exits 0 with no errors.

Fixes #2202

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