fix(frontend): submit Vercel drain grace period

[abcxff]

Summary

• include drainGracePeriod when creating serverless runner configs through the legacy-compatible payload branch
• share Vercel's 295-second request lifespan and validate drain grace periods below it
• default Vercel drain grace periods to 5 seconds in both standard and quick setup flows

Root cause

New runner configs have no existing protocolVersion, so the frontend selected the legacy-compatible payload branch. That branch omitted drainGracePeriod, causing the API to apply its 1800-second fallback, which is invalid for Vercel's 295-second request lifespan.

Verification

• pnpm --filter @rivetkit/engine-frontend check-types
• pnpm --filter @rivetkit/engine-frontend test (31 tests)
• pnpm --filter @rivetkit/engine-frontend build
• git diff --check

[railway-app]

🚅 Deployed to the rivet-pr-5517 environment in rivet-frontend

Service	Status	Web	Updated (UTC)
frontend-cloud	😴 Sleeping (View Logs)	Web	Aug 7, 2026 at 1:23 am
website	😴 Sleeping (View Logs)	Web	Aug 6, 2026 at 7:22 am
frontend-inspector	😴 Sleeping (View Logs)	Web	Aug 6, 2026 at 2:48 am
kitchen-sink	😴 Sleeping (View Logs)	Web	Aug 6, 2026 at 2:47 am
ladle	✅ Success (View Logs)	Web	Jul 30, 2026 at 10:11 pm
mcp-hub	✅ Success (View Logs)	Web	Jul 30, 2026 at 10:09 pm

[claude]

Review

Focused, well-scoped fix. Traced the root cause through buildServerlessConfig (connect-manual-serverless-frame.tsx) and confirmed the fix: the legacy-compatible payload branch (used when an existing runner config has no protocolVersion) previously omitted drainGracePeriod, so the API applied its 1800s fallback, which exceeds Vercel's ~295s function lifespan and broke deploys. Adding drainGracePeriod: values.drainGracePeriod to that branch directly addresses it.

Strengths

• Centralizing VERCEL_SERVERLESS_MAX_DURATION / VERCEL_REQUEST_LIFESPAN / VERCEL_DRAIN_GRACE_PERIOD in connect-vercel-form.tsx removes three previously-duplicated literals (VERCEL_SERVERLESS_MAX_DURATION - 5, drainGracePeriod: 0) across connect-vercel-frame.tsx and connect-quick-vercel-frame.tsx, so all three Vercel entry points (manual, standard, quick setup) now stay in sync.
• The new configurationSchema in connect-vercel-form.tsx correctly enforces drainGracePeriod < VERCEL_REQUEST_LIFESPAN (max 294, since VERCEL_REQUEST_LIFESPAN = 295), which is the right invariant to prevent a repeat of this bug via user input rather than just fixing the default.
• connect-quick-vercel-form.tsx now reuses ConnectVercelForm.configurationSchema.shape instead of the base (non-Vercel) schema, so the quick-setup flow picks up the same drain-grace-period bound the standard flow gets, previously it would have accepted unbounded values.

Minor / non-blocking

• connect-quick-vercel-form.tsx re-exports VERCEL_REQUEST_LIFESPAN/VERCEL_DRAIN_GRACE_PERIOD purely so connect-quick-vercel-frame.tsx can reach them through its ConnectVercelForm import alias (which actually points at the form module, one hop removed from where the constants are defined). It works and matches the file's existing re-export pattern for components, but is an extra indirection layer that's easy to lose track of. Importing connect-vercel-form.tsx directly under its own alias in the frame file would be more direct.
• The DrainGracePeriod field label/description (shared from connect-manual-serverless-form.tsx) does not surface the new upper bound to the user; the constraint is only discoverable via the validation error after submitting a too-large value. Not a blocker, just a UX nit.
• No automated coverage for the specific regression (schema bound, or the legacy-branch payload now including drainGracePeriod). There is no existing precedent for schema/payload-level tests in this directory, so this is optional, but this is exactly the kind of field-silently-dropped-in-one-of-two-branches bug a small buildServerlessConfig unit test would catch on future edits.

No correctness, security, or performance concerns beyond the above. This is client-side form/schema configuration only, with no new injection or trust-boundary surface.