feat(core,meta,app,android,ios): title logos and runtimes

ani.zip sent each series' TVDB clear logo and every episode's running
time from the start, and neither was kept. Enrichment now stores the logo
in title_metadata.logo_url (kept across a refresh of the same entry, like
the fanart) and episode runtimes in episode_metadata.runtime, TVDB's
first and AniDB's length after it. AniList's duration lands in
TitleDetails::runtime; TMDB episode runtimes are kept too.

Schema v13 adds the two columns and marks AniList titles un-enriched
without deleting anything. TitleDetails::revision lets details written
before runtime existed refetch by id while the old ones stay on screen,
instead of blanking them in the migration as v10 did.

Clear logos are padded to a square, so each client crops them to their
visible pixels before drawing. The logo replaces the name on the
library's banner and the title page (not on a light theme's title page,
where lettering made for dark art can vanish). Episode rows show how long
they run, in place of the file size on Android and iOS; a film's runtime
joins its line of facts.

docs/METADATA.md

@@ -170,6 +170,26 @@ AniList, so a search that finds nothing is asked again without it.
 
 Not done: TMDB fills no details.
 
+**Logos and running times.** ani.zip sent both from the start and neither was
+kept. Enrichment now keeps the series' TVDB *Clearlogo* — a transparent PNG —
+in `title_metadata.logo_url`, kept across a refresh of the same entry like the
+fanart, and each episode's running time (TVDB's, else AniDB's `length`) in
+`episode_metadata.runtime`. AniList's `duration` lands in
+`TitleDetails::runtime`: minutes per episode for a series, the whole running
+time for a film. TMDB's episode runtimes are kept the same way.
+
+A clear logo is padded to a square, so every client crops it to its visible
+pixels before drawing it (`trim_alpha` on the desktop, `opaqueBounds` on
+Android and iOS). It replaces the name over the library's banner and at the
+top of the title page — except on a light theme's title page, where lettering
+made for dark art could vanish. A film's running time joins its line of facts;
+an episode row shows its own (on Android and iOS in place of the file size).
+
+**Schema v13** adds the two columns and marks every AniList title un-enriched,
+deleting nothing. `TitleDetails::revision` makes details written before
+`runtime` existed refetch by id on the next run; they stay on screen until the
+answer lands, rather than being blanked by the migration as schema v10 did.
+
 ## Phase 3 — reach
 
 - **Local matching** against the offline database, so only ids leave the

docs/USER_GUIDE.md

@@ -72,6 +72,9 @@ Click a title to open its page. **Esc** goes back.
 - Each episode shows a tick when you have watched it. Right-click an episode and choose **Mark
   watched up to here** to tick it and every episode before it.
 - **In this franchise** lists the other parts of the series, when posters and descriptions are on.
+- With posters and descriptions on, a show's logo takes the place of its name at the top of the
+  page and on the library's banner, and each episode says how long it runs. A film says how long
+  it runs in the line under its name.
 
 An episode counts as watched once you have seen 90% of it.