fix(stats): ignored messages without IDs when parsing session entries

- Added message-ID checks in both assistant and user message parsers so entries without valid ids are ignored.
- This filtering prevents legacy, unlinked message records from being treated as parseable assistant or user messages.

packages/stats/src/parser.ts

@@ -31,6 +31,10 @@ function extractFolderFromPath(sessionPath: string): string {
 function isAssistantMessage(entry: SessionEntry): entry is SessionMessageEntry {
 	if (entry.type !== "message") return false;
 	const msgEntry = entry as SessionMessageEntry;
+	// Legacy sessions (pre-id tracking) recorded message entries without an `id`.
+	// They're not linkable and would violate the messages.entry_id NOT NULL
+	// constraint, so skip them at the parser boundary.
+	if (typeof msgEntry.id !== "string" || msgEntry.id.length === 0) return false;
 	return msgEntry.message?.role === "assistant";
 }
 
@@ -40,6 +44,7 @@ function isAssistantMessage(entry: SessionEntry): entry is SessionMessageEntry {
 function isUserMessage(entry: SessionEntry): entry is SessionMessageEntry {
 	if (entry.type !== "message") return false;
 	const msgEntry = entry as SessionMessageEntry;
+	if (typeof msgEntry.id !== "string" || msgEntry.id.length === 0) return false;
 	return msgEntry.message?.role === "user";
 }