framework tools/git: pr-review body-required actions fail fast (codex suggestion on PR #1464)

request-changes and comment both validate their required body
immediately after argument parsing (rc 2, stderr, zero provider
contact). The repo-host-override suite's action-message expectation
updated to the new wording; suite green.

packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh

@@ -218,7 +218,7 @@ if grep -q 'Unknown option' "$OUTPUT_FILE"; then
     cat "$OUTPUT_FILE" >&2
     exit 1
 fi
-grep -q 'Unknown action: bogus-action' "$OUTPUT_FILE"
+grep -q "unknown action 'bogus-action'" "$OUTPUT_FILE"
 
 # --- Case 2: -h/--help documents both overrides.
 HELP_TEXT="$("$SCRIPT_DIR/pr-review.sh" -h)"