v0.20.1

Fixed

• A transient failure of a collection-description read (a dropped connection, a
  5xx) is no longer taken for "no encryption descriptor".
  WasRemoteStore.readCollectionEncryption answers undefined only for a
  not-found response or a description with no encryption member; any other
  failure is thrown, wrapped with the collection id. A login fails its connected
  activation on it (falling back to local with the anonymous replica intact
  for a retry), a hot restore opens that collection fail-closed and still lands
  connected, the sync bootstrap skips the collection for the session with a
  warning, and the unknown-epoch refresh warns and leaves the cipher as it was.
• A transient failure of a collection's /meta read is no longer taken for "no
  metadata". WasRemoteStore.readCollectionMeta answers undefined only for a
  not-found response or a backend without metadata support (501); any other
  failure is thrown, wrapped with the collection id, and the sync bootstrap's
  blinded-index schema install warns and skips that collection.
• Neither read retries on its own: the HTTP client underneath already retries
  transient status codes and network errors, so a second retry layer only
  multiplied the attempts and the delay before a failure surfaced.
• A session that loses the attach-time storage-context claim (two providers
  booting at once, or a keyed remount overlapping the old provider's teardown)
  now closes the replica it opened before failing, instead of leaving an open
  RxDB database behind.
• StorageContext.detachStore now releases the active storage-context pointer
  when that context holds it, so every teardown (destroy(), logout,
  clear-data, the connected activation's fallback to local) releases it.
  Previously nothing did, and after a provider unmount the facades kept
  resolving the retired context; they now throw until the next boot claims a
  live one.
• A connected activation that fails and whose fallback to local also fails now
  surfaces the activation's own error; the fallback's is warned about.