fix(podcasts): code-review pass over the session's UI surfaces

Findings from the systematic gotcha-class review before the browser
pass:

- The collection smart editor's Apply derived the collection NAME from
  document.title — which parses to "Smart Collection", RENAMING the
  collection on every apply. The server now renders the real name
  (data-collection-name) and the write path refuses to proceed without
  it.
- TestRenderingPartialsRender pinned the pre-episode-collections
  empty-state copy ("No books in this collection yet.") — updated to
  the shipped label ("Nothing in this collection yet."; collections
  hold episodes now).
- The deleted handler-local rule comparators (evaluateRule/
  compareValues — removed in item 3.4's single-evaluator refactor)
  left behind two unit-test files testing the duplicates; deleted.
  Their semantics remain covered at the service level
  (TestEvaluateRules_* over FieldMatches/EvaluateRules) and
  TestTextToString (which actually pins utils.PgTextString) stays.

Everything else reviewed clean against the gotcha classes: templ
whole-expression attrs, ?={ boolean attrs, JSONArg quoting in
x-init/data attrs, Alpine CSP store paths, htmx form-encoding, the
" assert escaping, and the aria-label selector contract on the
player's reload listener.

templates/collection_rules.templ

@@ -20,6 +20,7 @@ templ CollectionRules(user User, collection CollectionData, fieldsJSON string, t
 		<body
 			class={ "theme-" + user.Theme }
 			x-data="collectionRules"
+			data-collection-name={ collection.Name }
 			x-init={ "initCollectionRules('" + collection.ID + "', '" + scope + "', " + JSONArg(treeJSON) + ")" }
 		>
 			@Header(user, "/collections")