fix(rooms): wire ?after= param to getRoomMessagesSince in messages GET route

[nyxsky404]

Summary

The room chat polling loop in MessageFeed sends ?after=<timestamp> to fetch only messages newer than the last seen one. The GET handler was reading ?before= exclusively, so after was silently ignored — every poll returned the same last-50 messages instead of only the new ones. This PR wires the after param to the already-existing getRoomMessagesSince helper.

Closes #2301

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Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

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What Changed

• src/app/api/rooms/[roomId]/messages/route.ts — added after param read from query string; branched to getRoomMessagesSince(roomId, after) for incremental polls and kept getRoomMessages(roomId, 50, before) for initial loads and reverse pagination
• Added getRoomMessagesSince to the import from @/lib/supabase-rooms

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How to Test

1. Open a collaboration room that already has some messages.
2. Open the browser Network tab and filter by the room's message endpoint.
3. In another browser session (same room), send a new message.
4. Observe the polling request: the response should now contain only the new message, not the full history.
5. Confirm the new message appears in the first session within ~5 seconds.

Expected result: Each poll response returns only messages sent after the last-known timestamp. Initial page load still returns the most recent 50 messages as before.

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Checklist

• Linked the related issue above
• Self-reviewed my own diff
• No unnecessary console.log, debug code, or commented-out blocks
• No TypeScript errors (pnpm run type-check — errors shown are all pre-existing)
• No new tests required — the logic change is a direct routing fix to an already-tested helper (getRoomMessagesSince has existing coverage in test/rooms-messages.test.ts)

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[nyxsky404]

The CI failures on this PR (Playwright smoke tests and Playwright visual regression) are pre-existing broken tests on main — they are not caused by the changes in this PR.

Root causes fixed:

• e2e/streak.spec.ts — duplicate aria-label on streak card div and tooltip button caused a strict-mode locator violation
• Visual regression — test heading selector @playwright-user's profile never matched the actual h1 (@playwright-user)
• landing-page-dark.png snapshot was accidentally zeroed in a prior merged commit
• Public profile test — no Supabase mock for server-side profile fetch in CI, so the page returned 404

Fixes have been applied to this branch. CI is Green.

[Priyanshu-byte-coder]

This PR has merge conflicts with the current main branch. Please rebase or merge main into your branch to resolve the conflicts, then push the updated branch. Once conflicts are resolved, this PR will be merged.

git fetch origin main
git merge origin/main
# resolve conflicts
git push