fix(loops): make detail page scroll and polish list rows

[charlesvien]

Problem

The loop detail page could not scroll: the root layout is overflow-hidden and the view never provided its own scroll container, so long loops (big instructions, run history) were clipped. The page also used a different content width than the list, the header actions were too small and the instructions textarea grew without bound. List rows showed a low-value trigger count and their colors did not match the template cards.

Changes

• Detail view scrolls in its own container and uses the same max-w-5xl px-8 py-8 column as the list, so switching pages no longer shifts content.
• Header actions (back, Run now, Edit, Delete) bumped from xs to sm.
• Instructions textarea capped at 400px and scrolls internally (quill Textarea is field-sizing: content, so it previously grew to fit the whole text).
• List rows: description now sits above the metadata line, metadata uses the template cards' accent color, and the trigger count is gone (the line is hidden when empty).

How did you test this?

Typecheck and Biome on @posthog/ui, plus visual iteration against the running dev app.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

[trunk-io]

😎 This pull request was merged.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "restyle loop list rows to match template..." | Re-trigger Greptile}

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 824de8e.}

[posthog]

✅ Visual changes approved by @charlesvien — baseline updated in 824de8e.

View this run in PostHog

4 changed.

[github-actions]

Contained UI polish (scroll container, spacing, row layout, show-more pagination) with matching snapshot updates and a bot-confirmed visual review; no risky territory touched and no outstanding concerns.

• Author wrote 27% of the modified lines and has 153 merged PRs in these paths (familiarity MODERATE).
• 👍 on the PR from greptile-apps[bot].

Gate mechanics and policy version

Gate		Result
prerequisites	✓	all clear
deny-list	✓	no deny categories matched
size	✓	69L, 4F substantive — within ceiling
tier	✓	T1-agent / T1b-small (69L, 4F, two-areas, fix)
stamphog 2.0.0b3		.stamphog/policy.yml @ cc35bdc · reviewed head 824de8e