fix(stats): harden duplicate-line cleanup and tracking

- Reject malformed requests and sub-day cleanup windows
- Reset deduplication across media and subtitle-track changes
- Handle karaoke bursts ending with a long hold frame

src/cli/args.test.ts

@@ -399,6 +399,28 @@ test('hasExplicitCommand and shouldStartApp preserve command intent', () => {
   assert.equal(statsLifetimeRebuild.statsCleanupLifetime, true);
   assert.equal(statsLifetimeRebuild.statsCleanupVocab, false);
 
+  assert.throws(
+    () =>
+      parseArgs([
+        '--stats',
+        '--stats-cleanup',
+        '--stats-cleanup-duplicate-lines',
+        '--stats-cleanup-lookback-days',
+        '0.5',
+      ]),
+    /at least one day/,
+  );
+  assert.equal(
+    parseArgs([
+      '--stats',
+      '--stats-cleanup',
+      '--stats-cleanup-duplicate-lines',
+      '--stats-cleanup-lookback-days',
+      '1.5',
+    ]).statsCleanupLookbackDays,
+    1,
+  );
+
   const jellyfinLibraries = parseArgs(['--jellyfin-libraries']);
   assert.equal(jellyfinLibraries.jellyfinLibraries, true);
   assert.equal(hasExplicitCommand(jellyfinLibraries), true);

src/cli/args.ts

@@ -112,6 +112,14 @@ export interface CliArgs {
 
 export type CliCommandSource = 'initial' | 'second-instance';
 
+function parseStatsCleanupLookbackDays(value: string | undefined): number {
+  const days = Number(value);
+  if (!Number.isFinite(days) || days < 1) {
+    throw new Error('Stats --lookback-days must be at least one day.');
+  }
+  return Math.floor(days);
+}
+
 export function parseArgs(argv: string[]): CliArgs {
   const args: CliArgs = {
     background: false,
@@ -376,11 +384,9 @@ export function parseArgs(argv: string[]): CliArgs {
     else if (arg === '--stats-cleanup-duplicate-lines') args.statsCleanupDuplicateLines = true;
     else if (arg === '--stats-cleanup-dry-run') args.statsCleanupDryRun = true;
     else if (arg.startsWith('--stats-cleanup-lookback-days=')) {
-      const value = Number(arg.split('=', 2)[1]);
-      if (Number.isFinite(value) && value > 0) args.statsCleanupLookbackDays = Math.floor(value);
+      args.statsCleanupLookbackDays = parseStatsCleanupLookbackDays(arg.split('=', 2)[1]);
     } else if (arg === '--stats-cleanup-lookback-days') {
-      const value = Number(readValue(argv[i + 1]));
-      if (Number.isFinite(value) && value > 0) args.statsCleanupLookbackDays = Math.floor(value);
+      args.statsCleanupLookbackDays = parseStatsCleanupLookbackDays(readValue(argv[i + 1]));
     } else if (arg.startsWith('--stats-response-path=')) {
       const value = arg.split('=', 2)[1];
       if (value) args.statsResponsePath = value;