fix(plex): Restart only where an episode has a resume point; the Surprise draw is re-read, not redrawn

Show cards carry resumable (ShowState, from the same rollup) so a part-watched
show whose next episode is untouched offers Play, not a Continue and a Restart
that do the same thing; plexStarted is the one rule for cards and menus. The
Surprise rail's key sits under the discover root: whatever refreshes the rails
re-reads the draw (keep=) with its watch state now, kept past the 5-minute gc,
and only the reshuffle deals. Closing the player refreshes the Discover rails.
A show card's play acts on the last click only, and only where it was made.

backend/tests/test_plex_discover.py

@@ -331,6 +331,20 @@ def test_a_reshuffle_deals_other_titles_first(db, monkeypatch, override_dep):
     assert set(movies("/api/plex/surprise?scope=movie&exclude=m2&exclude=m3")) == {"m2", "m3"}
 
 
+def test_a_kept_draw_is_read_again_not_redrawn(db, monkeypatch, override_dep):
+    # The rail's draw stands until the ↻, but its cards' watch state moves: `keep` answers the titles on
+    # screen, in their order and as they stand now, a watched one included; the scope still bounds it.
+    user = _seed(db)
+    url = "/api/plex/surprise?scope=both&keep=m3&keep=sh1&keep=m1&keep=nope"
+    items = _get(db, user, monkeypatch, override_dep, url).json()["items"]
+    assert _ids(items) == ["m3", "sh1", "m1"]
+    by_id = {c["id"]: c for c in items}
+    assert by_id["m1"]["status"] == "watched"
+    assert by_id["m3"]["position_seconds"] > 0
+    movie_only = "/api/plex/surprise?scope=movie&keep=sh1&keep=m2"
+    assert _ids(_get(db, user, monkeypatch, override_dep, movie_only).json()["items"]) == ["m2"]
+
+
 def test_discover_scope_movie_excludes_shows(db, monkeypatch, override_dep):
     user = _seed(db)
     d = _get(db, user, monkeypatch, override_dep, "/api/plex/discover?scope=movie").json()

backend/tests/test_plex_query_conversion.py

@@ -18,6 +18,7 @@ from app.db import get_db
 from app.main import app
 from app.models import PlexItem, PlexLibrary, PlexSeason, PlexShow, PlexState, User
 from app.plex import rollup, sync
+from app.plex.cards import ShowState
 
 
 def _dt(day: int) -> datetime:
@@ -184,21 +185,50 @@ class TestRollup:
     def test_state_map_new_inprogress_watched(self, db):
         s = _seed(db)
         show, user = s["show"], s["user"]
-        # e1 in-progress, e2 new -> in_progress
-        assert rollup.state_map(db, user.id, [show.id]) == {show.id: "in_progress"}
+        # e1 in-progress, e2 new -> in_progress, and e1's resume point makes it resumable
+        assert rollup.state_map(db, user.id, [show.id]) == {show.id: ShowState("in_progress", True)}
         # empty input short-circuits
         assert rollup.state_map(db, user.id, []) == {}
         # a fresh user with no state -> new
         other = User(email="rollup-other@example.com")
         db.add(other)
         db.commit()
-        assert rollup.state_map(db, other.id, [show.id]) == {show.id: "new"}
-        # mark every episode watched for `user` -> watched
+        assert rollup.state_map(db, other.id, [show.id]) == {show.id: ShowState("new", False)}
+        # e1 finished, e2 untouched: part watched, but no episode to resume — Continue and Restart
+        # would both play e2 from its start
         db.execute(delete(PlexState).where(PlexState.user_id == user.id))
-        for e in db.execute(select(PlexItem).where(PlexItem.kind == "episode")).scalars():
-            db.add(PlexState(user_id=user.id, item_id=e.id, status="watched"))
+        e1, e2 = db.execute(
+            select(PlexItem).where(PlexItem.kind == "episode").order_by(PlexItem.episode_number)
+        ).scalars()
+        db.add(PlexState(user_id=user.id, item_id=e1.id, status="watched"))
         db.commit()
-        assert rollup.state_map(db, user.id, [show.id]) == {show.id: "watched"}
+        assert rollup.state_map(db, user.id, [show.id]) == {
+            show.id: ShowState("in_progress", False)
+        }
+        # mark every episode watched for `user` -> watched
+        db.add(PlexState(user_id=user.id, item_id=e2.id, status="watched"))
+        db.commit()
+        assert rollup.state_map(db, user.id, [show.id]) == {show.id: ShowState("watched", False)}
+
+    def test_the_grid_card_says_whether_a_show_has_an_episode_to_resume(
+        self, db, monkeypatch, override_dep
+    ):
+        s = _seed(db)
+        user = s["user"]
+        cards = {
+            i["id"]: i
+            for i in _get(db, user, monkeypatch, override_dep, "/api/plex/library").json()["items"]
+        }
+        assert cards["s1"]["resumable"] is True
+        db.execute(
+            delete(PlexState).where(PlexState.user_id == user.id, PlexState.position_seconds > 0)
+        )
+        db.commit()
+        cards = {
+            i["id"]: i
+            for i in _get(db, user, monkeypatch, override_dep, "/api/plex/library").json()["items"]
+        }
+        assert cards["s1"]["resumable"] is False
 
 
 def _fake_paginate(by_type):