mod: restore missing mod features from resync audit

Re-add KOReaderSyncActivity PUSH_ONLY mode (PR #1090):
- SyncMode enum with INTERACTIVE/PUSH_ONLY, deferFinish pattern
- Push & Sleep menu action in EpubReaderMenuActivity
- ActivityManager::requestSleep() for activity-initiated sleep
- main.cpp checks isSleepRequested() each loop iteration

Wire EndOfBookMenuActivity into EpubReaderActivity:
- pendingEndOfBookMenu deferred flag avoids render-lock deadlock
- Handles all 6 actions: ARCHIVE, DELETE, TABLE_OF_CONTENTS,
  BACK_TO_BEGINNING, CLOSE_BOOK, CLOSE_MENU

Add book management to reader menu:
- ARCHIVE_BOOK, DELETE_BOOK, REINDEX_BOOK actions with handlers

Port silent next-chapter pre-indexing:
- silentIndexNextChapterIfNeeded() proactively indexes next chapter
  when user is near end of current one, eliminating load screens

Add per-book letterbox fill toggle in reader menu:
- LETTERBOX_FILL cycles Default/Dithered/Solid/None
- Loads/saves per-book override via BookSettings
- bookCachePath constructor param added to EpubReaderMenuActivity

Made-with: Cursor

chat-summaries/2026-03-07_19-00-summary.md

@@ -0,0 +1,42 @@
+# KOReaderSyncActivity PUSH_ONLY Mode Re-addition
+
+**Date**: 2026-03-07
+**Branch**: `mod/master-resync`
+
+## Task
+
+Re-add the `PUSH_ONLY` sync mode to `KOReaderSyncActivity` that was lost during the upstream resync/ActivityManager migration (originally from PR #1090). This mode allows the reader to silently push local progress to the KOReader sync server and then enter deep sleep — no interactive UI.
+
+## Changes
+
+### `src/activities/reader/KOReaderSyncActivity.h`
+- Added `enum class SyncMode { INTERACTIVE, PUSH_ONLY }` to the class
+- Added `syncMode` constructor parameter (defaults to `INTERACTIVE`)
+- Added `deferFinish(bool success)`, `pendingFinish`, `pendingFinishSuccess` for safe async finish from blocking calls
+
+### `src/activities/reader/KOReaderSyncActivity.cpp`
+- Implemented `deferFinish()` — sets a flag that `loop()` picks up to call `setResult()`/`finish()`
+- `onEnter()`: In PUSH_ONLY mode, silently finish if no credentials (no error UI)
+- `performSync()`: In PUSH_ONLY mode, skip remote fetch entirely and go straight to `performUpload()`
+- `performUpload()`: In PUSH_ONLY mode, use `deferFinish()` instead of setting UI state on success/failure
+- `loop()`: Check `pendingFinish` first and perform deferred finish if set
+
+### `src/activities/ActivityManager.h`
+- Added `requestSleep()` / `isSleepRequested()` — allows activities to signal that the device should enter deep sleep. Checked by the main loop.
+
+### `src/main.cpp`
+- Added `activityManager.isSleepRequested()` check in the main loop, before the auto-sleep timeout check
+
+### `src/activities/reader/EpubReaderMenuActivity.h` / `.cpp`
+- Added `PUSH_AND_SLEEP` to the `MenuAction` enum
+- Added menu item `{PUSH_AND_SLEEP, STR_PUSH_AND_SLEEP}` between SYNC and CLOSE_BOOK
+
+### `src/activities/reader/EpubReaderActivity.cpp`
+- Added `#include "activities/ActivityManager.h"`
+- Added `PUSH_AND_SLEEP` case in `onReaderMenuConfirm`: launches `KOReaderSyncActivity` in `PUSH_ONLY` mode, then calls `activityManager.requestSleep()` on completion (regardless of success/failure)
+
+### `lib/I18n/translations/english.yaml` / `lib/I18n/I18nKeys.h`
+- Added `STR_PUSH_AND_SLEEP: "Push & Sleep"` and regenerated I18n keys
+
+## Follow-up Items
+- None