feat(core,app,android,cli,ios): sync the library and settings, verify a share before adding it

Sync carried only watch positions, so a second device started empty. The
per-installation history file now also carries per-key registers
(pstr-core::profile): every share with its link and custom password, the
playback, appearance and metadata settings, the TMDB key, hand-picked
matches and per-title track choices. Newer updated_at wins per key, a
removal travels as an empty register, and a first sync stamps at 0 so a
fresh install takes the library the other devices have instead of
overwriting it with defaults. Volume, mute and the device-only settings
(cache budget, Wi-Fi only, background audio, hardware decoding) stay out.
The secrets live only in the end-to-end encrypted Drive file, never in
shares.json. FORMAT_VERSION stays 1; an older build ignores the registers.

Adding a share stored it before opening the link, so a first failure left a
broken entry and every retry said "already configured". add_verified opens
the link first and stores nothing on failure, and only the new share is
crawled afterwards, so another broken share cannot fail the add.

Android drops picture-in-picture: the window sized the video wrongly and
background audio already covers leaving the app.

iOS sizes the Metal drawable on every layout, so the picture no longer
stretches after a rotation or a Split View resize. Settings show a save at
once rather than after the match run, and a failed save reverts and says
why. Both phone clients gain an activity banner naming what is running, and
the add-share, metadata and change-match forms show progress and errors in
place.

android/app/src/test/java/io/narl/protonstream/ui/AccountUiTest.kt

@@ -9,7 +9,7 @@ class AccountUiTest {
     @Test
     fun `the sync line says how long ago and what came in`() {
         val minute = 60_000L
-        assertEquals("Watch history syncs with your Drive", syncLine(AccountUiState(), 0))
+        assertEquals("Library, settings and watch history sync through your Drive", syncLine(AccountUiState(), 0))
         assertEquals("Synced just now", syncLine(AccountUiState(syncedAt = 0), 30_000))
         assertEquals("Synced 5 min ago", syncLine(AccountUiState(syncedAt = 0), 5 * minute))
         assertEquals(
@@ -21,7 +21,7 @@ class AccountUiTest {
     @Test
     fun `a failed sync is said in place of when it last worked`() {
         assertEquals(
-            "Watch history did not sync: offline",
+            "Did not sync: offline",
             syncLine(AccountUiState(syncedAt = 0, syncError = "offline"), 0),
         )
     }

android/app/src/test/java/io/narl/protonstream/ui/ScreenshotTest.kt

@@ -137,22 +137,22 @@ class ScreenshotTest {
 
     @Test
     fun `the shares page`() = capture("shares-phone") {
-        SharesScreen(LIBRARY.shares, { _, _, _ -> }, { _, _, _ -> }, {}, {}, null, {}, PaddingValues())
+        SharesScreen(LIBRARY.shares, { _, _, _ -> null }, { _, _, _ -> }, {}, {}, null, {}, PaddingValues())
     }
 
     @Test
     fun `the settings page`() = capture("settings-phone") {
-        SettingsScreen(LIBRARY, { _, _, _, _ -> }, {}, {}, {}, PaddingValues(), version = "1.0.0")
+        SettingsScreen(LIBRARY, { _, _, _, _ -> null }, {}, {}, {}, PaddingValues(), version = "1.0.0")
     }
 
     @Test
     fun `the playback settings`() = capture("settings-playback") {
-        SettingsScreen(LIBRARY, { _, _, _, _ -> }, {}, {}, {}, PaddingValues(), SettingsPage.Playback)
+        SettingsScreen(LIBRARY, { _, _, _, _ -> null }, {}, {}, {}, PaddingValues(), SettingsPage.Playback)
     }
 
     @Test
     fun `the storage settings`() = capture("settings-storage") {
-        SettingsScreen(LIBRARY, { _, _, _, _ -> }, {}, {}, {}, PaddingValues(), SettingsPage.Storage)
+        SettingsScreen(LIBRARY, { _, _, _, _ -> null }, {}, {}, {}, PaddingValues(), SettingsPage.Storage)
     }
 
     @Test