fix: tighten vague language across all prompt files

- Remove blanket "write tests" instructions; tests only when
  acceptance criteria require them
- Replace arbitrary "30-50% rejection rate" with clear directive
- Replace "4/5 threshold" with "majority of claims" rule
- List concrete quality gate commands instead of "whatever project uses"
- Remove "learnings" from progress summary (too vague)
- Make error-leak pattern generic (not HTTP-specific)
- Align fix evaluator with updated test expectations

prompts/generator/fix.md

@@ -8,7 +8,7 @@ You are fixing bugs or reducing tech debt from a prioritized list. Each story is
 2. Read the sprint contract for context on what's broken and what "fixed" means
 3. **Understand the root cause before changing anything.** Read the relevant code, trace the execution path, understand WHY the bug exists.
 4. Make the minimal change to fix the issue
-5. Write or update a test that would have caught this bug
+5. If the story's acceptance criteria require a regression test, write one
 6. Run quality gates
 7. Commit
 
@@ -16,7 +16,7 @@ You are fixing bugs or reducing tech debt from a prioritized list. Each story is
 
 - **Fix only what the story describes.** Do not fix adjacent issues, even if you notice them. Note them in progress.md for future iterations.
 - **Minimal diff.** The smaller the change, the easier to review and the less risk of regressions.
-- **Add a regression test.** Every bug fix should include a test that reproduces the bug and verifies the fix. If no test framework exists, note this in progress.md.
+- **Add a regression test only if the acceptance criteria require it.** Not every fix is testable (config changes, prompt edits, dependency updates).
 - **Preserve behavior.** For tech debt refactors, the external behavior must not change. Only internal structure should improve.
 
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