feat(fuse,core): thumbnails for videos and for our own uploads

Videos without a server thumbnail fell through to the local fallback,
which downloaded the whole file, failed to decode it as an image and
wrote the video off for good. Grab one frame with ffmpeg instead, a
second in or from the start for shorter clips. Probe for ffmpeg before
downloading, bound every run, and skip videos over 256 MiB.
Migration V32 gives the videos written off so far another try.

Those videos had no server thumbnail because our uploads never sent one.
Every upload path (bulk upload, drained mount writes, conflict copies,
new revisions and folder sync) now attaches a thumbnail rendered from
the local file, kept under the 60 KiB Proton's own clients use. Files
that are not images or videos, or cannot be decoded, upload bare as
before; a .ts file only counts as video with an MPEG-TS sync byte.

ffmpeg is a new optional dependency in the PKGBUILDs.

crates/pdfs-core/src/db/migrations.rs

@@ -9,7 +9,7 @@ use super::Db;
 use crate::Result;
 
 /// Current schema version. Bump on every forward migration added below.
-pub(super) const SCHEMA_VERSION: i64 = 31;
+pub(super) const SCHEMA_VERSION: i64 = 32;
 
 impl Db {
     pub(super) fn migrate(&self) -> Result<()> {
@@ -270,6 +270,20 @@ impl Db {
                 tx.execute_batch(MIGRATION_V31)?;
             }
         }
+        if current < 32 {
+            // Data only, so safe to repeat; each table is guarded for a very
+            // old fixture that never had it.
+            for table in ["photos", "album_photos"] {
+                let has_table: bool = tx.query_row(
+                    "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = ?1",
+                    [table],
+                    |row| row.get::<_, i64>(0),
+                )? > 0;
+                if has_table {
+                    tx.execute(&MIGRATION_V32.replace("{table}", table), [])?;
+                }
+            }
+        }
         tx.execute(
             "INSERT INTO sync_state (key, value) VALUES ('schema_version', ?1)
              ON CONFLICT(key) DO UPDATE SET value = excluded.value",
@@ -952,3 +966,10 @@ ALTER TABLE photos ADD COLUMN resolved_at INTEGER;
 CREATE INDEX IF NOT EXISTS idx_photos_unresolved ON photos(resolved_at);
 UPDATE photos SET resolved_at = strftime('%s','now') WHERE name IS NOT NULL;
 ";
+
+/// V32: give videos written off as un-thumbnailable another chance.
+///
+/// Before local video thumbnails, the fallback fed a video's bytes to the image
+/// decoder, which could only fail, and that failure was recorded as the
+/// permanent "no thumbnail" verdict. Run once per table in `{table}`.
+const MIGRATION_V32: &str = "UPDATE {table} SET thumb_state = 0 WHERE kind = 1 AND thumb_state = 2";

crates/pdfs-core/src/db/tests.rs

@@ -4235,6 +4235,48 @@ fn the_servers_photo_relation_groups_a_live_photo() {
 /// A database written before grouping existed opens, keeps its timeline, and
 /// shows every photo — a row with no `group_key` is its own group, which is how
 /// the gallery behaved before the column.
+#[test]
+fn migration_v32_retries_videos_written_off_as_unthumbnailable() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-db-v31-fixture-{}-{}.db",
+        std::process::id(),
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos()
+    ));
+    {
+        let db = Db::open(&path).unwrap();
+        db.photos_replace(&[
+            TimelineRow {
+                name: Some("VID-20260804-WA0023.mp4".into()),
+                ..TimelineRow::new("video", 300)
+            },
+            TimelineRow {
+                name: Some("broken.jpg".into()),
+                ..TimelineRow::new("photo", 200)
+            },
+        ])
+        .unwrap();
+        db.photo_set_thumb("video", THUMB_NONE, None).unwrap();
+        db.photo_set_thumb("photo", THUMB_NONE, None).unwrap();
+        let conn = rusqlite::Connection::open(&path).unwrap();
+        conn.execute_batch("UPDATE sync_state SET value = '31' WHERE key = 'schema_version';")
+            .unwrap();
+    }
+
+    let db = Db::open(&path).unwrap();
+    let state = |uid: &str| db.photos_by_uid(&[uid.into()]).unwrap()[0].thumb_state;
+    assert_eq!(state("video"), THUMB_UNKNOWN, "the video is tried again");
+    assert_eq!(
+        state("photo"),
+        THUMB_NONE,
+        "an undecodable photo stays written off"
+    );
+    drop(db);
+    let _ = std::fs::remove_file(&path);
+}
+
 #[test]
 fn migration_v30_leaves_a_v29_timeline_intact() {
     let path = std::env::temp_dir().join(format!(