docs(jellyfin): Shows is on providers, and the per-library door stays dead anyway

The `Shows` flip landed today (one field, proven in the server's own
`LibraryOptions` answer), so the posture table no longer calls it a silent file
index and `Music`/`Collections` are named as the remaining ones.

Two corrections the same day's measurements force:

- The per-library `POST /Items/{id}/Refresh` answered `204` and queued nothing
  both before the flip and after it — zero journal lines for ten minutes, and
  `Scan Media Library` kept `LastTaskResult=None, EndTimeUtc=None`, the never-run
  signature. The provider switch was never the reason that door is dead; only
  `POST /Library/Refresh` runs (204, then `Running` inside 15 s at 33 % CPU), and
  it walks every library, so a library-scoped pass has no door on this build.
  That paragraph also records the null-pair read that separates "never ran" from
  "just finished", and that query+body on the same call answers `400` with an
  empty body whatever the values.
- The key law: a plugin owns its own config file under its own
  `<PluginConfiguration>` root and omits null settings, so TVDB's `<ApiKey>`
  element never existed and `install` refused — which is what `MISSING key` had
  been reporting since October. PR #121 fixes the writer.

The `Shows` art census replaces speculation with the split that matters: 2,908 of
3,558 series+season carry a primary, 624 have no provider id, 26 have an id and no
poster. A `Download` campaign over them took 20 s and downloaded nothing, which is
the measurement that says identification is the only lever left.

serverAppConfigs-docs/Dankserver/Jellyfin.md

@@ -89,13 +89,16 @@ looks exactly like an unconfigured library.
 | Library | `CollectionType` | `EnableInternetProviders` | `EnableRealtimeMonitor` |
 |---|---|---|---|
 | `Movies` | movies | true (fixed 2026-11-02) | **false** |
-| `Shows` | tvshows | **false** | true |
+| `Shows` | tvshows | true (fixed 2026-11-02) | true |
 | `Music` | music | **false** | true |
 | `Collections` | boxsets | **false** | false |
 
-`Shows` and `Music` are silent file indexes in the sense above: a refresh answers
+`Music` and `Collections` are silent file indexes in the sense above: a refresh answers
 `204`, stores nothing, logs nothing. Any metadata or artwork work on either one
-starts by flipping the switch, never by firing a scan.
+starts by flipping the switch, never by firing a scan. `Shows` sat in that set
+until 2026-11-02; the door is `POST /Library/VirtualFolders/LibraryOptions` with
+the library's own `ItemId` (below), and `scripts/jellyfin-providers.sh verify` is
+the one command that says which libraries are still in it.
 
 **The per-library option door on 12.x is `POST /Library/VirtualFolders/LibraryOptions`**
 — `GET` there answers `405`, which is how the route announces itself. The 10.x doors
@@ -130,6 +133,15 @@ nothing to look up. Art coverage is capped by identification, not by the image d
 the items a campaign returns nothing for are the unidentified ones, and no image
 retry will change that.
 
+**A `Download` campaign over a library that is already dressed does nothing in
+seconds, and that is the measurement proving identification is the only lever
+left.** Run over all 753 series and 2,805 seasons of `Shows` on 2026-11-02 it
+classified 3,558 items in 20 s: 2,908 already carried a primary, 624 have no
+provider id at all, 26 have an id and no poster in TMDb — zero downloads. The
+artless remainder is not an image-door problem: it is the unnamed long tail (clip
+collections, `(Warhammer TV)`-shaped directories), and the lever is folder names
+or an identify pass, never another retry loop.
+
 **Series and season art is fetched; episode stills are not, deliberately.** Every
 episode query is a fresh provider round-trip — nothing caches per episode — measured
 at ~11 s per item beside ~2 s per series on the same host, with one hit in five in a
@@ -250,9 +262,17 @@ scripts/jellyfin-providers.sh verify    # plugin + key LENGTHS, never key bytes
 - **The homelab TVDB key is a licensed key** (its JWT claims say
   `community_supported: false`), so it needs **no PIN** — the optional
   `TVDB_PIN=` line exists only for a subscriber-shaped key.
-- **TVDB is installed and keyed but is not a metadata agent**: TMDb still
-  identifies everything. Enabling TVDB as a provider would re-fetch show
-  metadata across the library, so it is a deliberate, separate change.
+- **TVDB is installed but is not a metadata agent**: TMDb still identifies
+  everything. Enabling TVDB as a provider would re-fetch show metadata across
+  the library, so it is a deliberate, separate change.
+- **A plugin owns its own config file, under its own root, and omits null
+  settings** — so the element an installer wants to fill may simply not exist,
+  and its root is `<PluginConfiguration>`, not `<Configuration>`. TVDB's file had
+  no `<ApiKey>` element at all, which is why `install` refused with
+  `no place to write <ApiKey>` from October until the anchor fix: the secret sat
+  valid in `provider-keys` the whole time, and `verify`'s `MISSING key` was this
+  fault, not a missing key. The writer now anchors on the file's own root and
+  still refuses by name when a file has none.
 - **The deployer places the keys before it restarts jellyfin**
   (`ensure_provider_keys` in `scripts/deploy-remote.sh`) and warns instead of
   failing when `provider-keys` is absent, so a host without it still deploys.
@@ -302,15 +322,25 @@ anything. The fix is `systemctl --user restart jellyfin.service`, one POST after
 health answers, and then believe `ScheduledTasks` State at 130 % CPU, not the
 response code.
 
-**The door that scans is `POST /Library/Refresh` (204), and `ScheduledTasks` is the
-progress read.** Measured 2026-11-02 against a `Shows` library that had never been
-identified: the per-library `POST /Items/{id}/Refresh?Recursive=true` answers `204`
-and queues **nothing** — item census identical afterwards, `Scan Media Library`
-idle, journal silent — and it is still an empty `204` after a service restart, so
-that status code carries no information at all. `/Library/Refresh` walks every
-library; within seconds the journal names folders (`…/TVShows/…`,
-`EpisodeMetadataService`) and `GET /ScheduledTasks` reports
-`Scan Media Library | Running | 75 %` while the process sits near 200 % CPU.
+**The door that scans is `POST /Library/Refresh` (204), and `ScheduledTasks` is
+the progress read.** A task that has never completed answers
+`LastTaskResult=None, EndTimeUtc=None`, and that pair is what separates "never
+ran" from "finished a moment ago" — the difference between a door that is dead
+and one that merely answered `204`.
+
+**The per-library `POST /Items/{id}/Refresh` queues nothing, and the provider
+switch is not the reason.** Measured twice on 2026-11-02 against `Shows`: before
+the flip and again after it, the call answered `204`, the journal wrote zero lines
+over the following ten minutes, and `Scan Media Library` kept its never-run
+signature; a service restart changes nothing. `POST /Library/Refresh` does run —
+`204`, then `Running` inside 15 s at 33 % CPU — but it walks every library, so on
+this build a library-scoped metadata pass has no working door and the global one
+is the only lever.
+
+**That endpoint takes its parameters from one source.** The documented query form
+(empty body) and the JSON body form (no query) each parse; supplying both at once
+answers `400` with an empty body whatever the values, and `ValidationFailure` is
+rejected in the body while the query form accepts it.
 
 **`RefreshStatus` on the `GET /Library/VirtualFolders` record is not a progress
 read.** It stayed `Idle` through a scan that was verifiably running at 75 %. The