feat(collections): the rules-Apply path seeds the reversed default too

The creation seed (d56031f3) covered born-smart collections; a STATIC
collection that becomes smart through the rules editor's Apply landed
without any curated order — its dropdown stayed "Feed order" while
every other podcast smart collection opened reversed. Same decision,
same guardrails (2026-11-01 user approved closing this gap): a PUT
carrying an episodes-scope tree seeds chain_order=reverse only when
neither the request NOR the stored view_settings names one — a
deliberate native (client-sent or saved) is never clobbered, and
books-scope trees seed nothing.

Pins: apply-seeds-when-unordered, respects-stored-native,
respects-client-native (TestSmartCollectionBornReversed now covers
both seed paths); changelogged in contract_pins.

internal/handlers/collections.go

@@ -607,6 +607,27 @@ func (h *CollectionHandler) UpdateCollection(c *echo.Context) error {
 	if treeErr != nil {
 		return c.JSON(http.StatusBadRequest, map[string]string{"error": treeErr.Error()})
 	}
+	// Applying a tree to a collection with NO curated listening order
+	// seeds the reversed default (2026-11-01 — the creation seed's twin):
+	// a static collection becoming smart lands with the same default a
+	// born-smart one gets. Triple-guarded: the client's explicit
+	// chain_order wins, a STORED chain_order is never clobbered, and
+	// only episodes-scope trees seed (books have no episode chain).
+	if treeJSON != nil && (req.ViewSettings == nil || req.ViewSettings["chain_order"] == nil) {
+		if t, perr := services.ParseFilterTree(string(treeJSON)); perr == nil &&
+			t.FilterScope() == services.ScopeEpisodes {
+			if existing, gerr := h.collectionService.GetCollection(c.Request().Context(), collectionID); gerr == nil {
+				var stored map[string]interface{}
+				_ = json.Unmarshal(existing.ViewSettings, &stored)
+				if stored == nil || stored["chain_order"] == nil {
+					if req.ViewSettings == nil {
+						req.ViewSettings = map[string]interface{}{}
+					}
+					req.ViewSettings["chain_order"] = "reverse"
+				}
+			}
+		}
+	}
 	collection, err := h.collectionService.UpdateCollection(
 		c.Request().Context(),
 		collectionID,