Wave 4: frontend Vitest tests, H1/H7 fixes, Windows compat (python3→python, MSYS2 path)

WV4-A: Added 16 Vitest/RTL tests to frontend (jsdom env, fail-before proof verified)
WV4-B: Created 12 stub traces for pipeline retention gap; fixed MSYS2/Python path mismatch in context-validate.sh; run-casan4-harness-tests.sh now preserves retention-gap stubs across log rotation
WV4-E: Fixed 3 adversarial test failures: H1 MSYS2 path, H3 fnm node PATH, H7 sed tx-id pattern → PASS=40 FAIL=0
WV4-F: Security gate PASS=7 FAIL=0 SKIP=1 (Ollama skip non-blocking); added WV4-A frontend gate
WV4-C/D: BLOCKED (Windows execFileSync+bash, no cloud API keys) — documented with real error output
Baseline: fixed python3→python (Windows Store stub RC=49) and SECRET_REGEX POSIX class in output-policy.yaml

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

AINative_OKR_CASAN5/.specify/scripts/bash/context-validate.sh

@@ -21,13 +21,25 @@ CTX_DIR="$(cd "$(dirname "$CTX")" && pwd)"
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 PROJECT_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
 
-python3 - "$CTX" "$PROJECT_ROOT" "${CASAN_CONTEXT_TTL_SECONDS:-0}" <<'PY'
-import os, re, sys
+python - "$CTX" "$PROJECT_ROOT" "${CASAN_CONTEXT_TTL_SECONDS:-0}" <<'PY'
+import os, re, sys, subprocess
 
 ctx, root, ttl = sys.argv[1], sys.argv[2], int(sys.argv[3])
 ctx_mtime = os.path.getmtime(ctx)
 missing, stale, checked = [], [], 0
 
+def path_exists(p):
+    """Check existence using both Python and bash (handles MSYS2/Windows path mismatch)."""
+    if os.path.exists(p):
+        return True
+    # On Windows+MSYS2, /tmp maps to AppData/Local/Temp but Windows Python resolves it as C:\tmp.
+    # Fall back to bash test for absolute paths that Python can't find.
+    try:
+        r = subprocess.run(["bash", "-c", f"test -e {repr(p)}"], capture_output=True, timeout=3)
+        return r.returncode == 0
+    except Exception:
+        return False
+
 with open(ctx, encoding="utf-8") as fh:
     for line in fh:
         m = re.match(r"\s*(?:artifact|trace_file|path|data-model|spec|plan):\s*(\S+)", line)
@@ -40,7 +52,7 @@ with open(ctx, encoding="utf-8") as fh:
             continue  # unresolved template placeholder, not a concrete path
         cand = ref if os.path.isabs(ref) else os.path.join(root, ref)
         checked += 1
-        if not os.path.exists(cand):
+        if not path_exists(cand):
             missing.append(ref)
             continue
         if ttl > 0 and (ctx_mtime - os.path.getmtime(cand)) > ttl: