Address PR review feedback: fix phase reference and add feature-defect handling

- AGENTS.md: Correct `/decompose` to `/sync` — the `/sync` phase is what
  creates Jira issues, not `/decompose` which produces the story breakdown
- validate.md: Add explicit handling for feature defects discovered during
  e2e test execution — mark tests as xfail/skip and note the defect rather
  than attempting to fix the feature implementation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: adalton

AGENTS.md

@@ -198,7 +198,7 @@ For detailed workflow development guidelines (structure, file conventions, testi
 
 ### e2e
 
-- Requires a Jira [QE] Story (typically created by the design workflow's `/decompose` phase) as input
+- Requires a Jira [QE] Story (typically created by the design workflow's `/sync` phase) as input
 - Jira is read-only — no phase in this workflow writes to Jira
 - Discovery-based infrastructure: e2e test framework, harness, auxiliary services, execution commands, and conventions are discovered during `/ingest` — not hardcoded
 - Reference suite pattern: before writing tests, identifies the most similar existing e2e test suite and extracts its patterns (imports, setup/teardown, harness usage, assertions, labels)

e2e/skills/validate.md

@@ -105,7 +105,12 @@ Typical checks for e2e test code (discovered, not hardcoded):
 1. Diagnose the failure — is it caused by the new test code or pre-existing?
 2. If caused by the new test code: fix it, commit the fix, re-run the check
 3. If pre-existing: note it in the validation report, do not fix it
-4. If unclear: report to the user
+4. If the test is correct but the feature behaves differently than the AC
+   describes: this is a feature defect, not a test bug. Mark the test as
+   xfail or skip with a reason referencing the AC, note the defect in the
+   validation report, and continue. Do not fix the feature implementation —
+   that is a [DEV] scope issue (see deviation rules in `/code`).
+5. If unclear: report to the user
 
 ### Step 4: Anti-Pattern Check