fix(r5): address the fourth /code-review high round — 6 findings

- Feed memoizes onClose (like Playlists already did): the inline closure re-ran
  PlayerModal's keydown effect on every Feed render, which since the debounce
  landed also flushed the volume write and re-stole focus
- the player reads its volume with readAccountMerged again — a partial stored
  object made the level undefined -> NaN -> a persisted null; applyVolume also
  refuses a non-finite level outright
- that read moved into a lazy useState initializer (was running per render)
- the two RSS except branches share one tail, so a counter can't drift again
- run_ffmpeg tests cover the SIGTERM->SIGKILL escalation and the lingering-
  process path; dropped an assertion that only restated the fixture
- storage.ts documents the actual { volume } shape (0 IS muted)

backend/app/sync/runner.py

@@ -74,28 +74,26 @@ def run_rss_poll(db: Session, channels: list[Channel] | None = None) -> dict[str
             channel = futures[fut]
             try:
                 entries = fut.result()
-            except RssError as exc:
+            except Exception as exc:
                 # A failed poll is NOT an empty feed: skip the apply so `last_rss_at` stays where
                 # it was. Stamping it here made a permanently-broken feed look freshly polled.
-                log.warning("RSS poll skipped for channel %s: %s", channel.id, exc)
+                # An RssError is an EXPECTED outcome (404, timeout) → one warning line; anything
+                # else is a bug on our side and earns a traceback.
+                if isinstance(exc, RssError):
+                    log.warning("RSS poll skipped for channel %s: %s", channel.id, exc)
+                else:
+                    log.exception("RSS fetch failed for channel %s", channel.id)
                 failed += 1
-                done += 1
-                progress.report(done, total, "rss_poll")
-                continue
-            except Exception:
-                log.exception("RSS fetch failed for channel %s", channel.id)
-                failed += 1
-                done += 1
-                progress.report(done, total, "rss_poll")
-                continue
-            try:
-                new += apply_rss_feed(db, channel, entries)
-            except Exception:
-                # A write failure (read-only DB, failover) leaves the channel just as un-polled as
-                # an unreachable feed — count it, or a wholly broken run still reports "failed=0".
-                db.rollback()
-                failed += 1
-                log.exception("RSS apply failed for channel %s", channel.id)
+            else:
+                try:
+                    new += apply_rss_feed(db, channel, entries)
+                except Exception:
+                    # A write failure (read-only DB, failover) leaves the channel just as un-polled
+                    # as an unreachable feed — count it, or a wholly broken run reports "failed=0".
+                    db.rollback()
+                    failed += 1
+                    log.exception("RSS apply failed for channel %s", channel.id)
+            # One place that advances the counter, whatever happened above.
             done += 1
             progress.report(done, total, "rss_poll")
     if failed: