fix(tts): skip hidden footnotes in TTS, closes #4135 (#4193)

Footnotes/endnotes are hidden in the rendered page via `display: none`,
but TTS builds its blocks from its own document. For background
sections that document is raw XHTML loaded via `section.createDocument()`
without the page layout styles, so the footnotes were read aloud.

- `createRejectFilter` gains an `attributeTokens` option to match
  `aside[epub:type~="footnote|endnote|note|rearnote"]` (value-token
  match, like CSS `[attr~="x"]`), so footnotes are detectable on raw
  documents that lack the `epubtype-footnote` class.
- `TTSController` adds the footnote selectors to its reject filter.
- `getBlocks()` (foliate-js) skips the subtree of any block-level
  element the node filter rejects, ending the preceding block before
  it so footnote text doesn't leak in.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/readest-app/src/utils/node.ts

@@ -2,11 +2,18 @@ export const createRejectFilter = ({
   tags = [],
   classes = [],
   attributes = [],
+  attributeTokens = [],
   contents = [],
 }: {
   tags?: string[];
   classes?: string[];
   attributes?: string[];
+  /**
+   * Reject elements whose space-separated attribute value contains any of the
+   * given tokens, optionally constrained to a tag name. Matches the way CSS
+   * `[attr~="token"]` selectors work — e.g. `aside[epub:type~="footnote"]`.
+   */
+  attributeTokens?: { tag?: string; attribute: string; tokens: string[] }[];
   contents?: { tag: string; content: RegExp }[];
 }) => {
   return (node: Node): number => {
@@ -24,6 +31,17 @@ export const createRejectFilter = ({
       if (attributes.some((attr) => (node as Element).hasAttribute(attr))) {
         return NodeFilter.FILTER_REJECT;
       }
+      if (
+        attributeTokens.some(({ tag, attribute, tokens }) => {
+          if (tag && name !== tag) return false;
+          const value = (node as Element).getAttribute(attribute);
+          if (!value) return false;
+          const valueTokens = value.split(/\s+/);
+          return tokens.some((token) => valueTokens.includes(token));
+        })
+      ) {
+        return NodeFilter.FILTER_REJECT;
+      }
       if (
         contents.some(({ tag, content }) => {
           return name === tag && content.test((node as Element).textContent || '');