Add Per-Team Branded Share Subdomains On lawn.video (PROMPT)

[PraiseXI]

Problem

Share links currently use the app’s current origin, so teams do not get a branded share URL.

Relevant places:

• src/components/ShareDialog.tsx
• app/routes/dashboard/-project.tsx
• convex/schema.ts
• convex/shareLinks.ts

If the intended product direction is to keep shared links on lawn.video, then teams should still be able to get team-specific
share URLs without needing full custom domain setup.

Goal

Add per-team share subdomains on lawn.video, for example:

• https://acme.lawn.video/share/<token>
• https://acme.lawn.video/watch/<publicId>

This should preserve the repo’s priorities:

• performance above all else
• good defaults
• convenience
• security

Why This Approach

Compared to full custom domains, team subdomains on lawn.video are:

• simpler to configure
• faster to ship
• easier to make the default
• less likely to create auth/cookie/domain edge cases
• more consistent with a low-friction share workflow

This fits the project better than making users manage DNS in v1.

Scope

In scope:

• assign each team a share subdomain on lawn.video
• use that subdomain automatically for public watch links and restricted share links
• generate/copy/open links using that team subdomain by default
• add any necessary host resolution for incoming share traffic

Out of scope unless straightforward:

• user-provided custom domains
• moving the dashboard app to team subdomains
• advanced brand customization beyond the hostname

Requirements

• Each team gets a unique, stable subdomain on lawn.video
• Subdomains should be generated with good defaults from the team slug or another stable team identifier
• Collisions must be handled safely
• Copied share links should use the team’s subdomain automatically
• Existing share protections must keep working:
  • expiration
  • password protection
  • download flags
• The implementation must not weaken auth or expose the wrong team’s content on the wrong host

Suggested Implementation

Data model

Add a team-level share hostname/subdomain field or derived hostname strategy.

At minimum:

• a unique team share slug/subdomain
• validation and collision handling
• ability to resolve incoming hostnames to the correct team

URL generation

Replace window.location.origin-based share URL generation with:

• https://<team-subdomain>.lawn.video for eligible share/watch links
• fallback to the default app origin where necessary

This should require no extra setup for normal users.

Routing

Add host-based resolution for share pages so the incoming *.lawn.video hostname maps to the correct team context.

Defaults

Prefer automatic defaults:

• generate the share subdomain from the team slug if possible
• avoid adding a settings flow unless needed
• keep the common path instant and simple

Security Requirements

• Subdomains must be unique and tied to exactly one team
• A team’s subdomain must not expose another team’s share links
• Existing share-link auth rules must continue to apply
• Public endpoints should be reviewed carefully for host-based isolation issues

Performance Requirements

• Share-link creation and copying should remain immediate
• Avoid unnecessary client-side waterfalls
• Avoid per-link configuration
• Keep the default share workflow as fast as it is now

Acceptance Criteria

• A team has a stable share subdomain on lawn.video
• Public watch and restricted share links use that subdomain by default
• Visiting the subdomain link loads the correct shared video page
• Existing share protections still work
• The implementation keeps the share flow fast and low-friction
• Team isolation remains intact