burn: Fix PR template — remove duplication, strengthen proof enforcement

- Eliminated duplicate content (entire template was repeated twice)
- Renamed 'Linked Issue' to 'Governing Issue' per CONTRIBUTING.md language
- Added explicit 'no proof = no merge' callout in Proof section
- Renamed 'What was tested' to 'Commands / logs / world-state proof' for clarity
- Enhanced checklist with items from #393: issue reference, syntactic validity, proof standard
- Added inline guidance comments referencing CONTRIBUTING.md

Closes #451

.gitea/PULL_REQUEST_TEMPLATE.md

@@ -2,7 +2,7 @@
 
 <!-- What changed and why. One paragraph max. -->
 
-## Linked Issue
+## Governing Issue
 
 <!-- REQUIRED. Every PR must reference at least one issue. Max 3 issues per PR. -->
 <!-- Closes #ISSUENUM -->
@@ -10,18 +10,20 @@
 
 ## Acceptance Criteria
 
-<!-- What specific outcomes does this PR deliver? Check each when proven. -->
+<!-- List the specific outcomes this PR delivers. Check each only when proven. -->
+<!-- Copy these from the governing issue if it has them. -->
 
 - [ ] Criterion 1
 - [ ] Criterion 2
 
 ## Proof
 
-### What was tested
-
-<!-- Paste the exact commands, output, log paths, or world-state artifacts that prove the acceptance criteria were met. -->
 <!-- No proof = no merge. See CONTRIBUTING.md for the full standard. -->
 
+### Commands / logs / world-state proof
+
+<!-- Paste the exact commands, output, log paths, or world-state artifacts that prove each acceptance criterion was met. -->
+
 ```
 $ <command you ran>
 <relevant output>
@@ -42,8 +44,11 @@ $ <command you ran>
 
 ## Checklist
 
-- [ ] Proof meets CONTRIBUTING.md standard (exact commands, output, or artifacts)
-- [ ] Python files pass syntax check (`python -c "import ast; ast.parse(open('file.py').read())"`)
-- [ ] Shell scripts are executable (`chmod +x`)
+<!-- Complete every item before requesting review. -->
+
+- [ ] PR body references at least one issue number (`Closes #N` or `Refs #N`)
+- [ ] Changed files are syntactically valid (`python -c "import ast; ast.parse(open(f).read())"`, `node --check`, `bash -n`)
+- [ ] Proof meets CONTRIBUTING.md standard (exact commands, output, or artifacts — not "looks right")
 - [ ] Branch is up-to-date with base
 - [ ] No more than 3 unrelated issues bundled in this PR
+- [ ] Shell scripts are executable (`chmod +x`)