fix: headless EXIT_RELOAD case + notification dedup boundary

- src/headless-events.ts: add case "reload" → EXIT_RELOAD (12).
  EXIT_RELOAD sentinel was defined but unused — "reload" status fell
  through to EXIT_ERROR (1).
- src/resources/extensions/sf/notification-store.ts:109: use <= for
  dedup window so a second identical notification at exactly
  DEDUP_WINDOW_MS still gets suppressed (was off-by-one at boundary).
- src/resources/extensions/sf/definition-loader.ts: pending docstring
  tweaks from autonomous sweep.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/headless-events.ts

@@ -43,6 +43,8 @@ export function mapStatusToExitCode(status: string): number {
 			return EXIT_BLOCKED;
 		case "cancelled":
 			return EXIT_CANCELLED;
+		case "reload":
+			return EXIT_RELOAD;
 		default:
 			return EXIT_ERROR;
 	}

src/resources/extensions/sf/definition-loader.ts

@@ -19,6 +19,9 @@ import { parse } from "yaml";
 
 // ─── Public TypeScript Types (camelCase) ─────────────────────────────────
 
+/**
+ * Step verification policy: content-heuristic, shell-command, prompt-verify, or human-review.
+ */
 export type VerifyPolicy =
 	| { policy: "content-heuristic"; minSize?: number; pattern?: string }
 	| { policy: "shell-command"; command: string }
@@ -32,6 +35,9 @@ export interface IterateConfig {
 	pattern: string;
 }
 
+/**
+ * Workflow step definition with prompt, dependencies, produced artifacts, and optional verification.
+ */
 export interface StepDefinition {
 	/** Unique step identifier within the workflow. */
 	id: string;

src/resources/extensions/sf/notification-store.ts

@@ -106,7 +106,7 @@ export function appendNotification(
 		: `${_basePath}:${severity}:${source}:${persistedMessage}`;
 	const now = Date.now();
 	const lastSeen = _recentMessageTimestamps.get(dedupKey);
-	if (lastSeen !== undefined && now - lastSeen < DEDUP_WINDOW_MS) return;
+	if (lastSeen !== undefined && now - lastSeen <= DEDUP_WINDOW_MS) return;
 	_recentMessageTimestamps.set(dedupKey, now);
 	if (_recentMessageTimestamps.size > DEDUP_PRUNE_THRESHOLD) {
 		for (const [key, ts] of _recentMessageTimestamps) {
@@ -347,7 +347,7 @@ function _withLock<T>(basePath: string, fn: () => T): T {
 				try {
 					const stat = readFileSync(lockPath, "utf-8");
 					const lockTime = parseInt(stat, 10);
-					if (Date.now() - lockTime > 5000) {
+					if (Number.isFinite(lockTime) && Date.now() - lockTime > 5000) {
 						try {
 							unlinkSync(lockPath);
 						} catch {