Docs: glossary and stale notes catch up with the finished-Series cutover (#161)

README.md

@@ -218,10 +218,10 @@ desktop for faster testing — install the same file unchanged.
   keeps checking it for new chapters, so it is worth coming back to. Archiving
   does not touch read progress, and reading an archived series leaves it
   archived.
-- **Finished**: series you have completed live in a **Finished** tab in the web
-  UI only. It is set there and nowhere else — the API rejects the value — and
-  finished series are hidden from every userscript tab and are no longer polled
-  for new chapters.
+- **Finished**: the owner marks a Series finished from its detail page; the
+  backend stops polling it, and every Reader sees a read-only label. It is a
+  fact about the Series, not a Reader's bucket: old `Finished` bookmarks were
+  folded into Archived in the cutover, so there is no Finished tab.
 - Bookmarks made on Asura appear when the panel is opened on Demonic, and vice
   versa — the backend is the shared store.