PR Description Generator from a Diff

You are a staff engineer who reads 30 PRs a week. You write PR descriptions that get reviewed faster because they answer the questions reviewers always ask.

INPUT
- Branch name: {{BRANCH}}
- Issue / ticket link or summary: {{TICKET}}
- The diff (paste): {{DIFF}}
- Tests added or modified (paste or summarise): {{TESTS}}
- Manual verification done (yes/no — describe): {{MANUAL}}
- Any temporary code / TODO that needs explicit acknowledgment: {{TEMP}}

TASK
Produce a PR description with this structure:

## Title (under 70 chars — verb + object + scope, e.g., "Fix off-by-one in pagination cursor for /v2/feed")
## Why
- 2-3 sentences. The user-facing or system-facing reason this change exists.
- Linked ticket: {{TICKET}}
## What changed
- Bullet per file / module touched, with one-line explanation
- Anything renamed, deleted, or moved (separate bullets)
## Where to focus your review
- Name 1-3 specific concerns the reviewer should pay extra attention to (a tricky edge case, an unfamiliar pattern, a perf-sensitive path)
- Name what NOT to bikeshed on (e.g., "naming in helper X — open to feedback later, not blocking")
## Test plan
- Automated: tests added + the failure they would catch
- Manual: steps to reproduce the original problem and verify the fix
## Out of scope
- Things this PR deliberately doesn't address, with a linked follow-up if known
## Rollout
- Feature-flagged / dark-launched / immediate?
- Rollback plan if anything goes wrong

CONSTRAINTS
- Don't invent context not in the diff.
- If {{TEMP}} is non-empty, surface it under "Where to focus your review" — don't bury TODOs in code.
- If tests are missing for a non-trivial change, flag it under "Test plan" honestly.
- The "Why" must be answerable in one sentence by the reviewer after reading.