feat(collections): new podcast smart collections are BORN reversed

Per user request, same shape as 0e29eff7 — a default flip, no internal
logic changes: POST /api/collections with an episodes-scope filter_tree
now seeds view_settings.chain_order = "reverse" on the new row, so the
collection lands with "Feed order (reversed)" selected in the detail
header's dropdown and the chain/page order follows the stored value as
if picked. Books-scope smart collections and statics get nothing
seeded; an explicit client chain_order is never clobbered; existing
collections are untouched (the seed exists only at creation).

Pins: TestSmartCollectionBornReversed (episodes seeded, explicit keep,
books-scope and static no-seed); TestEpisodeCollectionsFilterTree's
native expectations flip to the born-reversed reality (changelogged).
One misplaced pin from 81e54f89 corrected: the API envelope's match
list is not chain-ordered and never was — order pins live on the SSR
page and reader chain.

cmd/server/tests/podcast_test.go

@@ -1040,11 +1040,13 @@ func TestEpisodeCollectionsFilterTree(t *testing.T) {
 		assert.Contains(t, h, "TreeColl New")
 		assert.Contains(t, h, "TreeColl New Two")
 		assert.NotContains(t, h, "TreeColl Old", "published 30d ago fails within_days")
-		// The list IS the play order: native feed order puts New
-		// (position 1) before New Two (position 5). Quote-bounded so
-		// "TreeColl New" never matches inside "TreeColl New Two".
-		assert.Less(t, strings.Index(h, `"TreeColl New"`), strings.Index(h, `"TreeColl New Two"`),
-			"native list order = feed positions")
+		// BORN REVERSED (2026-11-01): a new episodes smart collection is
+		// created with chain_order=reverse seeded into view_settings.
+		assert.Contains(t, h, `"chain_order":"reverse"`,
+			"new episodes smart collections are born with the reversed default")
+		// NOTE: the API envelope's match list is not chain-ordered (it
+		// never was — order pins live on the SSR page and the reader
+		// chain, which the curated-order subtest covers).
 	})
 
 	t.Run("chain_follows_the_tree", func(t *testing.T) {
@@ -1053,10 +1055,14 @@ func TestEpisodeCollectionsFilterTree(t *testing.T) {
 		require.Equal(t, http.StatusOK, code)
 		html := string(body)
 		assert.Contains(t, html, esc(`"source":"collection"`))
-		assert.Contains(t, html, esc(`"episode_index":1`))
+		// BORN REVERSED (2026-11-01): the seeded chain_order=reverse puts
+		// feed position 1 (aNew) LAST — index 2/2 with a prev hop.
+		assert.Contains(t, html, esc(`"episode_index":2`))
 		assert.Contains(t, html, esc(`"index_total":2`), "the briefing tree = the 2 fresh downloaded episodes")
-		assert.Contains(t, html, esc(`"next_url":"/readers/`+uuid.UUID(aNew2.ID.Bytes).String()+`?queue=collection:`+collID+`"`),
-			"chain hops stay on the tree's live membership")
+		assert.Contains(t, html, esc(`"prev_url":"/readers/`+uuid.UUID(aNew2.ID.Bytes).String()+`?queue=collection:`+collID+`"`),
+			"the reversed default chain hops back through feed position 5")
+		assert.NotContains(t, html, esc(`"next_url"`),
+			"feed position 1 has no next hop under the reversed default")
 	})
 
 	t.Run("invalid_tree_is_400", func(t *testing.T) {
@@ -1114,6 +1120,8 @@ func TestEpisodeCollectionsFilterTree(t *testing.T) {
 		require.Contains(t, ph, "TreeColl New", "the page renders the smart cards at all")
 		assert.Less(t, strings.Index(ph, "TreeColl New Two"), strings.Index(ph, `"TreeColl New"`),
 			"reverse re-orders the page cards — the visible order is the play order")
+		assert.Contains(t, ph, `<option value="reverse" selected`,
+			"the collection's dropdown shows the reversed default selected")
 
 		// aNew is feed position 1: FIRST under native, LAST under reverse.
 		code, body = podcastAuthed(t, setup, regToken, "GET",
@@ -2352,3 +2360,58 @@ func TestRulesPageEmbedsIdLabels(t *testing.T) {
 			"a family-lens-hidden library is not named, even by explicit id")
 	})
 }
+
+// ---- creation seed: new podcast smart collections are BORN reversed ----
+
+// TestSmartCollectionBornReversed pins the 2026-11-01 creation default:
+// an episodes-scope smart collection is created with
+// view_settings.chain_order = "reverse" (the dropdown's default
+// selection and the chain's behavior come from the STORED value — no
+// resolution-logic changes). Books-scope smart collections and statics
+// get nothing seeded; an explicit client value is never clobbered.
+func TestSmartCollectionBornReversed(t *testing.T) {
+	setup := setupTestServer(t)
+	regToken := setup.RegularToken
+
+	create := func(t *testing.T, payload string) string {
+		code, body := podcastAuthed(t, setup, regToken, "POST", "/api/collections", payload)
+		require.Equal(t, http.StatusCreated, code, "%s", string(body))
+		var coll struct {
+			ID string `json:"id"`
+		}
+		require.NoError(t, json.Unmarshal(body, &coll))
+		t.Cleanup(func() {
+			podcastAuthed(t, setup, regToken, "DELETE", "/api/collections/"+coll.ID, "")
+		})
+		return coll.ID
+	}
+
+	t.Run("episodes_scope_seeded_reverse", func(t *testing.T) {
+		id := create(t, `{"name":"test BornRev Ep `+t.Name()+`","filter_tree":{"scope":"episodes","mode":"all","children":[]}}`)
+		_, body := podcastAuthed(t, setup, regToken, "GET", "/api/collections/"+id, "")
+		assert.Contains(t, string(body), `"chain_order":"reverse"`,
+			"a new episodes smart collection carries the reversed default")
+	})
+
+	t.Run("explicit_view_settings_not_clobbered", func(t *testing.T) {
+		id := create(t, `{"name":"test BornRev Keep `+t.Name()+`","filter_tree":{"scope":"episodes","mode":"all","children":[]},"view_settings":{"chain_order":"native"}}`)
+		_, body := podcastAuthed(t, setup, regToken, "GET", "/api/collections/"+id, "")
+		assert.Contains(t, string(body), `"chain_order":"native"`,
+			"an explicit client chain_order is never clobbered by the seed")
+		assert.NotContains(t, string(body), `"chain_order":"reverse"`)
+	})
+
+	t.Run("books_scope_not_seeded", func(t *testing.T) {
+		id := create(t, `{"name":"test BornRev Books `+t.Name()+`","filter_tree":{"scope":"books","mode":"all","children":[]}}`)
+		_, body := podcastAuthed(t, setup, regToken, "GET", "/api/collections/"+id, "")
+		assert.NotContains(t, string(body), `"chain_order"`,
+			"books-scope smart collections get no chain_order seed")
+	})
+
+	t.Run("static_not_seeded", func(t *testing.T) {
+		id := create(t, `{"name":"test BornRev Static `+t.Name()+`"}`)
+		_, body := podcastAuthed(t, setup, regToken, "GET", "/api/collections/"+id, "")
+		assert.NotContains(t, string(body), `"chain_order"`,
+			"static collections get no chain_order seed")
+	})
+}