Add Pinchflat-style media manager: index channels into playlist folders

Index an entire YouTube channel or playlist once, then download it into
organized <Channel>/<Playlist>/<NNN> - <Title> folders, with incremental
re-sync. Built in six rebuild-gated phases (F-K); see ROADMAP-PINCHFLAT.md.

- F: channel-walk indexer (/playlists + /videos) -> persisted Source +
  MediaItem JSON stores; pure classify/dedup logic in indexerCore.ts
- G: Windows-safe folder paths + dir sanitizer (collectionOutputTemplate)
- H: Library tab + source tree + "Download pending" into the existing queue
- I: state-preserving re-index merge + persist-downloaded-on-complete
- J: watched sources, RSS fast-check, Task Scheduler + --sync launch
  (the OS-level scheduling/RSS need a real-install smoke test)
- K: .info.json / thumbnail / .description sidecars for media servers

Also gitignore .gitea-token. 106 unit tests pass; typecheck + build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/sources.ts

@@ -0,0 +1,135 @@
+/**
+ * Persistence for the media-manager index (Pinchflat-style; see
+ * ROADMAP-PINCHFLAT.md). Two plain-JSON stores in userData, mirroring the
+ * history.ts pattern (and the same deliberate choice to stay on JSON rather than
+ * better-sqlite3 — revisit if a user indexes many large channels, see the
+ * Phase H risk note in the roadmap):
+ *
+ *   sources.json      — one Source record per added channel/playlist
+ *   media-items.json  — every MediaItem across all sources (queried by sourceId)
+ *
+ * Per-row validation on read (validation.ts) so a hand-edited or corrupted file
+ * can't feed the UI malformed records (same approach as history/errorlog).
+ */
+
+import { app } from 'electron'
+import { join } from 'path'
+import { readFileSync, writeFileSync, existsSync } from 'fs'
+import type { Source, MediaItem } from '@shared/ipc'
+import { isValidSource, isValidMediaItem } from './validation'
+import { mergeItemsPreservingState } from './indexerCore'
+
+// A generous global cap so a runaway index can't grow the file unbounded; large
+// enough for several big channels. When exceeded, the most-recently-written
+// source's items are kept (they're placed first by replaceMediaItems).
+const MAX_ITEMS = 20000
+
+function sourcesFile(): string {
+  return join(app.getPath('userData'), 'sources.json')
+}
+
+function itemsFile(): string {
+  return join(app.getPath('userData'), 'media-items.json')
+}
+
+function readJsonArray<T>(path: string, isValid: (o: unknown) => o is T): T[] {
+  try {
+    if (!existsSync(path)) return []
+    const data = JSON.parse(readFileSync(path, 'utf8'))
+    return Array.isArray(data) ? data.filter(isValid) : []
+  } catch {
+    return []
+  }
+}
+
+function writeJson(path: string, value: unknown): void {
+  try {
+    writeFileSync(path, JSON.stringify(value, null, 2))
+  } catch {
+    /* best-effort; a read-only data dir just means no persisted index */
+  }
+}
+
+// --- Sources ----------------------------------------------------------------
+
+export function listSources(): Source[] {
+  return readJsonArray(sourcesFile(), isValidSource)
+}
+
+export function getSource(id: string): Source | undefined {
+  return listSources().find((s) => s.id === id)
+}
+
+/** Insert or replace a source by id (a re-index updates the existing record). */
+export function upsertSource(source: Source): Source[] {
+  const sources = [source, ...listSources().filter((s) => s.id !== source.id)]
+  writeJson(sourcesFile(), sources)
+  return sources
+}
+
+/** Toggle whether a source is watched for new uploads (Phase J). Returns all sources. */
+export function setSourceWatched(id: string, watched: boolean): Source[] {
+  const sources = listSources().map((s) => (s.id === id ? { ...s, watched } : s))
+  writeJson(sourcesFile(), sources)
+  return sources
+}
+
+/** Remove a source and all of its media items. Returns the remaining sources. */
+export function removeSource(id: string): Source[] {
+  const sources = listSources().filter((s) => s.id !== id)
+  writeJson(sourcesFile(), sources)
+  const items = listAllItems().filter((m) => m.sourceId !== id)
+  writeJson(itemsFile(), items)
+  return sources
+}
+
+// --- Media items ------------------------------------------------------------
+
+function listAllItems(): MediaItem[] {
+  return readJsonArray(itemsFile(), isValidMediaItem)
+}
+
+export function listMediaItems(sourceId: string): MediaItem[] {
+  return listAllItems().filter((m) => m.sourceId === sourceId)
+}
+
+/**
+ * Replace all media items for one source with a fresh set (the result of a
+ * (re)index). Other sources' items are preserved; the new items are placed first
+ * so they survive the MAX_ITEMS cap.
+ */
+export function replaceMediaItems(sourceId: string, items: MediaItem[]): void {
+  const others = listAllItems().filter((m) => m.sourceId !== sourceId)
+  writeJson(itemsFile(), [...items, ...others].slice(0, MAX_ITEMS))
+}
+
+/**
+ * Incrementally merge a freshly-indexed item list into the persisted store,
+ * preserving the downloaded state of videos already on disk (see Phase I). The
+ * fresh list defines current membership/order; returns the merged items and how
+ * many were new since the last index.
+ */
+export function mergeMediaItems(
+  sourceId: string,
+  fresh: MediaItem[]
+): { items: MediaItem[]; newCount: number } {
+  const result = mergeItemsPreservingState(listMediaItems(sourceId), fresh)
+  replaceMediaItems(sourceId, result.items)
+  return result
+}
+
+/**
+ * Mark one media item downloaded, recording its file path + time. Returns the
+ * updated list for that item's source (or [] if the id is unknown). Used by the
+ * library view once a queued item completes (Phase H/I).
+ */
+export function setMediaItemDownloaded(id: string, filePath?: string): MediaItem[] {
+  const all = listAllItems()
+  const target = all.find((m) => m.id === id)
+  if (!target) return []
+  const updated = all.map((m) =>
+    m.id === id ? { ...m, downloaded: true, downloadedAt: Date.now(), filePath } : m
+  )
+  writeJson(itemsFile(), updated)
+  return updated.filter((m) => m.sourceId === target.sourceId)
+}