feat(podcasts): the rules page retires — the collection builder IS the filter builder (item 3.4)

The smart-collection editor at /collections/:id/rules now hosts the
SAME builder island as All-Books (FilterBuilderRows — the rows markup
extracted into one shared templ both mounts render; the shared
filterBuilderExtra component). One vocabulary, one engine, one row UI;
the collection differences are exactly three: the payload is the
collection's scope (episode trees get the episode fields — books
trees hide them), Apply writes the tree to the collection (PUT
filter_tree through the validated write path), and a legacy rules
array preloads as its CONVERTED tree (RulesToFilterTree rendered
server-side) so the upgrade lands at the first Apply — read-compat
never mutates data silently.

Retired with the page: the per-rule CRUD endpoints and test-rules
(their handler bodies, routes, api-docs rows, and the dead collections.ts
island functions — the file's LIVE halves, the collection modal/navigate/
grid-refresh, stay; the dead rules half went). match-mode endpoint and
preview survive (legacy channel + the dashboard custom-section-builder,
flagged for its own migration). Contract-pin changelog documents the
deletions per the asymmetry rule.

The builder component gains collection mounts: scopeKey (the row
universe for counts/apply), data-tree prefill, treeJSON (the apply
wire with scope riding the top level), and an apply hook (the page
owns the write; All-Books never sets one). ensureReadyRule defaults to
the scope's first field instead of hardcoding author.

Tests migrated onto trees: TestSmartCollections' live-membership /
reject-mutations / include-auto / system-collection subtests now drive
TREE collections; the deleted-endpoint subtests die with them.

internal/docs/schema.go

@@ -835,22 +835,6 @@ var Schemas = map[string]Schema{
 	"DELETE /api/devices/:id/file-aliases/:aliasId": {
 		Response: json.RawMessage(`{"message": ""}`),
 	},
-	"POST /api/collections/:id/rules": {
-		// First rule converts a static collection to smart.
-		Request: handlers.AddRuleRequest{},
-		Response: json.RawMessage(`{
-			"collection_id": "", "rule": {}, "is_smart": false
-		}`),
-	},
-	"DELETE /api/collections/:id/rules/:ruleId": {
-		Response: json.RawMessage(`{
-			"collection_id": "", "is_smart": false
-		}`),
-	},
-	"POST /api/collections/test-rules": {
-		Request:  handlers.TestRulesRequest{},
-		Response: json.RawMessage(`{"matches": [], "total": 0}`),
-	},
 	"POST /api/collections/:id/books": {
 		// Bulk add: {operations: [{collection_id, book_ids:[...]}]}.
 		Request: json.RawMessage(`{