chore: re-baseline the PR template on the org one

[LukasWodka]

Re-baselines this repo's .github/pull_request_template.md on the org template, keeping only the checks that are genuinely specific to this repo. Implements the recommendation on backend#1373.

This repo is one of just two (with the other of client/cli) that earns its own template — the other eight are being deleted so they inherit the org one, because their copies were byte-identical, strictly older subsets, or differed only in which repo the cross-repo example named.

What this changes. The body is now the org template verbatim, plus the repo-specific checklist lines that were already here. Net effect beyond that:

• picks up the expand-then-contract line for cross-repo changes (docs: expand-then-contract for cross-repo changes .github#111);
• picks up the note that closing keywords don't fire on a develop merge (docs: note that closing keywords do not fire on a develop merge .github#113) — a caveat this repo had locally, now shared with everyone;
• restores anything this copy had drifted away from the shared template.

Ongoing cost, stated plainly: because this repo keeps its own file, future org-template changes will not reach it automatically — it will need re-baselining again. That is the price of the repo-specific lines, and it is why only two repos keep one.

---

Note

Low Risk
Documentation-only change to the PR template; no runtime or application behavior.

Overview
Re-baselines .github/pull_request_template.md on the org template, while keeping this repo’s Go build/vet/lint and STYLE.md checklist lines at the bottom.

Adds org-wide guidance: Breaking change type, Screenshots / recordings and Deployment notes sections, clearer Test plan prompt, and checklist items for docs, security reviewers, and expand-then-contract cross-repo rollouts. The Related comment now uses tracebloc/client-runtime#456 and notes that closing keywords don’t fire when merging to develop.

^{Reviewed by Cursor Bugbot for commit 00b0ca1. Bugbot is set up for automated code reviews on this repo. Configure here.}

[LukasWodka]

👋 Heads-up — Code review queue is at 49 / 30

Above the WIP limit. The team convention is to review existing PRs before opening new work.

Open PRs currently in Code review (oldest first):

• averaging-service#255 — chore(ci): enable Dependabot security updates · author: @LukasWodka · no reviewer assigned
• averaging-service#256 — chore: adopt the org PR template · author: @LukasWodka · no reviewer assigned
• backend#1146 — docs(rfc): platform cost & autoscaling architecture · author: @saadqbal · reviewer: @LukasWodka, @saqlainsyed007, @aptracebloc
• backend#1201 — docs(rfc): Data spaces & federated dataset composition (draft) · author: @LukasWodka · reviewer: @saadqbal
• backend#1217 — docs(rfc): Dataset integrity & score reproducibility (draft) · author: @LukasWodka · reviewer: @saadqbal
• backend#1261 — RFC-BACKEND-0008: board & process reset (decision RFC — for markup) · author: @LukasWodka · reviewer: @saadqbal
• backend#1284 — docs(deploy): backend deploy runbook skeleton (#1263) · author: @LukasWodka · no reviewer assigned
• backend#1332 — feat(check-model): allow KNN/GaussianProcess on a single-edge owned dataset (#923 follow-up) · author: @divyasinghds · no reviewer assigned
• backend#1353 — chore(ci): baseline historical gitleaks findings + wire caller · author: @LukasWodka · no reviewer assigned
• backend#1361 — feat(tasks): bound ExperimentQueue growth for PAUSED experiments (backend#1351) · author: @saqlainsyed007 · reviewer: @aptracebloc

Pull from review before opening new work. (This is a nudge from the kanban WIP check, not a block.)

[LukasWodka]

/fr-pass