refactor(tokenizer): address review feedback on Yomitan scan runtime

- extract the injected scan runtime (helpers, install script, call-script
  builder) into tokenizer/yomitan-scan-runtime-script.ts; the host module drops
  from ~2700 to ~1900 lines
- append the kana run to the reading as well as the surface when an unparsed
  run extends the previous token, so the reading keeps covering the surface and
  the known-word reading fallback stays enabled (bumps scan runtime version)
- stop annotateMs before character-image resolution so the stage timing
  measures the annotation stage only

src/core/services/tokenizer.ts

@@ -920,8 +920,8 @@ export async function tokenizeSubtitle(
   if (yomitanTokens && yomitanTokens.length > 0) {
     const annotateStartedAtMs = Date.now();
     const annotatedTokens = await applyAnnotationStage(yomitanTokens, deps, annotationOptions);
-    const renderedTokens = applyCharacterNameImages(annotatedTokens, deps, annotationOptions);
     stageTimings.annotateMs = Date.now() - annotateStartedAtMs;
+    const renderedTokens = applyCharacterNameImages(annotatedTokens, deps, annotationOptions);
     logStageTimings(renderedTokens.length);
     return {
       text: displayText,