## What kind of change does this PR introduce?
Bug fix for the Vercel Deploy Button → Studio handoff.
## What is the current behavior?
Vercel sometimes opens our install popup with `source=marketplace` while
still sending Deploy Button params (`currentProjectId`, `external-id`).
We trust `source` alone, so users are routed to choose-project (connect)
instead of create — which is why create never gets reached in the Deploy
Button flow.
## What is the new behavior?
- When both Deploy Button signals (`currentProjectId` + `externalId`)
are present, route to create even if Vercel sent `source=marketplace` /
`external`
- Hide Skip (and related empty-state copy) on choose-project when those
signals are present, so Deploy Button users can't continue without
linking
## Additional context
Stacked on #48230.
Test plan:
- [ ] Unit tests for `resolveVercelInstallSource` /
`hasVercelDeployButtonSignals` pass
- [ ] Deploy Button flow with mislabeled `source=marketplace` + both
params → lands on create after org install/continue
- [ ] Genuine marketplace install (no `currentProjectId`/`external-id`)
→ still lands on choose-project with Skip available
- [ ] If choose-project is opened with both Deploy Button params, Skip
is hidden
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- **New Features**
- Improved Vercel installation handling for Deploy Button workflows,
ensuring the correct setup path is selected.
- Added clearer project-connection guidance when no projects are
available (including conditional skip copy).
- **Bug Fixes**
- Prevented Deploy Button installations from incorrectly offering a skip
option.
- Preserved the skip-and-connect-later guidance for other Vercel
installation flows.
- Improved recognition of Deploy Button installations even when the
reported Vercel source differs.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: Joshen Lim <joshenlimek@gmail.com>
## Context
For the Vercel integration flow (e.g "Deploy with Vercel" button on GH)
If an organization has no projects, there currently isn't a way to
create a project and connect it in the same session - users can only hit
"Skip".
This addresses that by directing users to the /deploy-button/new-project
route in this scenario
<img width="505" height="539" alt="image"
src="https://github.com/user-attachments/assets/6cc85030-42c7-4e58-b4b3-cb8ac0f5da9e"
/>
## Other changes involved
- Also separates `ProjectLinker` into smaller components - preference
for avoiding declaration of components within a component
## To test
I'm not sure if this can be tested on staging to be honest, but
otherwise we can give it a go on production after the changes are
through, as this doesn't change any existing logic to the usual "Connect
project" flow
I did try clicking the "Deploy with Vercel" button on a repo, and just
changing the URL to the staging URL at the Supabase step - seems to work
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
## Summary
* **UI Improvements**
* Streamlined the Vercel/GitHub project-linking step while keeping the
same create/connect/skip flow, including the searchable project picker,
branding/status indicators, and the feature-flagged “create new project”
option.
* On the Vercel choose-project step, the default selection now reflects
the current project context.
* **Bug Fixes / Tests**
* Improved Vercel install routing query handling to preserve
deploy-button configuration when present, with updated automated test
coverage.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: Danny White <3104761+dnywh@users.noreply.github.com>
Danny White