[Fix] PR filter repo info is not left-aligned on mobile

[roomote-roomote]

Opened on behalf of Matt Rubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

Related issue

N/A — requested directly from Slack product feedback on the tasks PR filter sheet.

Why this PR exists

• A maintainer explicitly invited this PR in the linked issue or discussion
• I am a maintainer / this is internal Roomote work

What changed

On mobile, the task filters PR picker bottom sheet showed recent PR repo/number lines (e.g. RooCodeInc/Roomote#240) centered under the titles because dropdown checkbox items render as native <button> elements. Those items now force full-width, left-aligned content so the muted repo#number sublabels line up with the PR titles. The same dual-line content treatment is applied consistently for model filter options that use sublabels.

How it was tested

• Prettier check and ESLint on the changed files
• Pre-push: pnpm lint:fast, pnpm check-types:fast, and pnpm knip
• Mobile screenshot of the PR filter sheet with recent multi-line PR rows confirming left-aligned repo#number sublabels

Checklist

• The PR title follows the repo convention: [Fix], [Feat], [Improve], [Refactor], [Docs], or [Chore] followed by a user-facing description
• This PR is small and scoped to one change
• pnpm lint and pnpm check-types pass locally
• I added tests or included a clear manual validation note above
• I removed secrets, tokens, private keys, and customer data from code, logs, and screenshots
• If this change should appear in the changelog, I ran pnpm changeset

Screenshots

[roomote-roomote]

No code issues found. This is a focused, CSS-only fix that left-aligns the PR/model filter sublabels in the mobile dropdown sheet. See task

_{Reviewed 14c1be1}