feat: add "Mark Unwatched" toggle for movies on web and native (#52)

- Replace the static "Mark Watched" button with a toggle that shows "Mark Unwatched" (destructive style) when a movie is already completed
- Add `handleUnwatchMovie` to web `useTitleActions` with optimistic update (reverts status to `in_watchlist` on error)
- Add `unwatchMovie` mutation to native `useTitleActions` hook and `titleActions` imperative helper
- Update poster-card and upcoming-row context menus to show the correct action based on current watch status
- Wire the `M` keyboard shortcut on the title detail page to unwatch when the movie is already marked watched
- Add i18n strings for "Mark Unwatched", "Marked as unwatched", and "Failed to mark as unwatched"

packages/i18n/src/po/en.po

@@ -346,7 +346,6 @@ msgstr ""
 msgid "Added \"{titleName}\" to watchlist"
 msgstr ""
 
-#: apps/native/src/hooks/use-title-actions.ts
 #: apps/native/src/hooks/use-title-actions.ts
 #: apps/native/src/lib/title-actions.ts
 #: apps/web/src/components/titles/use-title-actions.ts
@@ -1236,7 +1235,6 @@ msgstr "Export"
 msgid "Failed"
 msgstr ""
 
-#: apps/native/src/hooks/use-title-actions.ts
 #: apps/native/src/lib/title-actions.ts
 msgid "Failed to add to watchlist"
 msgstr ""
@@ -1293,6 +1291,12 @@ msgstr ""
 msgid "Failed to mark all episodes as watched"
 msgstr ""
 
+#: apps/native/src/hooks/use-title-actions.ts
+#: apps/native/src/lib/title-actions.ts
+#: apps/web/src/components/titles/use-title-actions.ts
+msgid "Failed to mark as unwatched"
+msgstr "Failed to mark as unwatched"
+
 #: apps/native/src/hooks/use-title-actions.ts
 #: apps/native/src/lib/title-actions.ts
 #: apps/web/src/components/titles/use-title-actions.ts
@@ -1386,7 +1390,6 @@ msgstr ""
 msgid "Failed to update rating"
 msgstr ""
 
-#: apps/native/src/app/(tabs)/(settings)/index.tsx
 #: apps/web/src/components/settings/registration-section.tsx
 msgid "Failed to update registration setting"
 msgstr ""
@@ -1860,6 +1863,13 @@ msgstr "Mark episode {epNum} watched"
 msgid "Mark Episode Watched"
 msgstr "Mark Episode Watched"
 
+#: apps/native/src/app/title/[id].tsx
+#: apps/native/src/components/dashboard/upcoming-row.tsx
+#: apps/native/src/components/ui/poster-card.tsx
+#: apps/web/src/components/titles/title-actions.tsx
+msgid "Mark Unwatched"
+msgstr "Mark Unwatched"
+
 #: apps/web/src/components/command-palette.tsx
 msgid "Mark watched"
 msgstr "Mark watched"
@@ -1871,6 +1881,10 @@ msgstr "Mark watched"
 msgid "Mark Watched"
 msgstr ""
 
+#: apps/native/src/app/title/[id].tsx
+msgid "Marked \"{name}\" as unwatched"
+msgstr "Marked \"{name}\" as unwatched"
+
 #: apps/native/src/app/title/[id].tsx
 msgid "Marked \"{name}\" as watched"
 msgstr "Marked \"{name}\" as watched"
@@ -1879,6 +1893,11 @@ msgstr "Marked \"{name}\" as watched"
 #~ msgid "Marked \"{titleName}\" as completed"
 #~ msgstr ""
 
+#: apps/native/src/lib/title-actions.ts
+#: apps/web/src/components/titles/use-title-actions.ts
+msgid "Marked \"{titleName}\" as unwatched"
+msgstr "Marked \"{titleName}\" as unwatched"
+
 #: apps/native/src/lib/title-actions.ts
 #: apps/web/src/components/titles/use-title-actions.ts
 msgid "Marked \"{titleName}\" as watched"
@@ -1898,6 +1917,12 @@ msgstr "Marked all episodes of \"{titleName}\" as watched"
 #~ msgid "Marked as completed"
 #~ msgstr ""
 
+#: apps/native/src/app/title/[id].tsx
+#: apps/native/src/hooks/use-title-actions.ts
+#: apps/native/src/lib/title-actions.ts
+msgid "Marked as unwatched"
+msgstr "Marked as unwatched"
+
 #: apps/native/src/app/title/[id].tsx
 #: apps/native/src/hooks/use-title-actions.ts
 #: apps/native/src/lib/title-actions.ts