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.

ios/ProtonStreamTests/UiLogicTests.swift

@@ -51,7 +51,7 @@ final class IncomingShareLinkTests: XCTestCase {
 final class AccountUiTests: XCTestCase {
     func testTheSyncLineSaysHowLongAgoAndWhatCameIn() {
         let zero = Date(timeIntervalSince1970: 0)
-        XCTAssertEqual(syncLine(AccountUiState(), now: zero), "Watch history syncs with your Drive")
+        XCTAssertEqual(syncLine(AccountUiState(), now: zero), "Library, settings and watch history sync through your Drive")
         XCTAssertEqual(syncLine(AccountUiState(syncedAt: zero), now: zero.addingTimeInterval(30)), "Synced just now")
         XCTAssertEqual(syncLine(AccountUiState(syncedAt: zero), now: zero.addingTimeInterval(300)), "Synced 5 min ago")
         XCTAssertEqual(
@@ -64,7 +64,7 @@ final class AccountUiTests: XCTestCase {
         let zero = Date(timeIntervalSince1970: 0)
         XCTAssertEqual(
             syncLine(AccountUiState(syncedAt: zero, syncError: "offline"), now: zero),
-            "Watch history did not sync: offline"
+            "Did not sync: offline"
         )
     }