gate scripts: chmod +x python after build, fix crash grep word boundary

build_phoenix.sh: add chmod +x after binary verification (LTO builds
sometimes produce non-executable binaries).
gate_phoenix.sh: use -w word boundary in crash grep to avoid matching
test_crashers test name as a false positive crash.

Author: SonicField

scripts/build_phoenix.sh

@@ -190,11 +190,12 @@ if [ "$MAKE_EXIT" -ne 0 ]; then
 fi
 rm -f "$MAKE_LOG"
 
-# Step 7: Verify binary exists
+# Step 7: Verify binary exists and is executable
 if [ ! -f "$CPYTHON_ROOT/python" ]; then
     echo "FAIL: python binary not built"
     exit 1
 fi
+chmod +x "$CPYTHON_ROOT/python"
 
 echo "=== Build complete ==="
 echo "Binary: $CPYTHON_ROOT/python"

scripts/gate_phoenix.sh

@@ -136,7 +136,7 @@ echo "CPython: $CPYTHON_TOTAL_TESTS tests, $CPYTHON_FILES_RUN/$CPYTHON_FILES_TOT
 echo "$CPYTHON_SUMMARY" | tee -a "$RESULTS_FILE"
 
 # Check for crashes (hard failures)
-CPYTHON_CRASHES=$(echo "$CPYTHON_OUTPUT" | grep -c -E "CRASH|Segmentation fault|Aborted" || true)
+CPYTHON_CRASHES=$(echo "$CPYTHON_OUTPUT" | grep -c -wE "CRASH|Segmentation fault|Aborted" || true)
 CPYTHON_CRASHES=${CPYTHON_CRASHES:-0}
 if [ "$CPYTHON_CRASHES" -gt 0 ]; then
     GATE_PASS=0