feat: issue templates — bug, feature, push3-seed, refactor (#678)

Four templates for Codeberg issue creation:

- **Bug** — what, repro steps, affected files, acceptance criteria
- **Feature** — problem, solution, affected files (incl e2e tests), max 5 acceptance criteria
- **Push3 Seed** — strategy philosophy, behavior spec, pre-filled reference files + register mapping
- **Refactor** — what, approach, affected files, risks

All templates require affected files and acceptance criteria — the two things the dev-agent needs most. Push3 seed template has pre-filled deps (#667) and reference docs.

Gardener agent can enforce these on unstructured issues that come in without templates.

Co-authored-by: openhands <openhands@all-hands.dev>
Reviewed-on: https://codeberg.org/johba/harb/pulls/678
Reviewed-by: review_bot <review_bot@noreply.codeberg.org>

.woodpecker/e2e.yml

@@ -12,6 +12,7 @@ when:
       - "tools/**"
       - "onchain/test/FitnessEvaluator*"
       - "docs/**"
+      - ".codeberg/**"
       - "*.md"
 
 clone: