Replace grammar-ending permutations with shared matcher; preserve word a

- Extract `grammar-ending.ts` with `isStandaloneGrammarEndingText` / `isSubtitleGrammarEndingText` pattern matchers
- Replace `STANDALONE_GRAMMAR_ENDINGS` set in parser-selection-stage with shared matcher
- Replace generated phrase sets in subtitle-annotation-filter with shared matcher
- Remove stale duplicate subtitle-exclusion constants and helpers from annotation-stage
- Manual clipboard card updates now write only to the sentence audio field, leaving word/expression audio untouched

docs-site/mining-workflow.md

@@ -100,7 +100,7 @@ If you prefer a hands-on approach (animecards-style), you can copy the current s
    - For multiple lines: press `Ctrl/Cmd+Shift+C`, then a digit `1`–`9` to select how many recent subtitle lines to combine. The combined text is copied to the clipboard.
 3. Press `Ctrl/Cmd+V` to update the last-added card with the clipboard contents plus audio, image, and translation — the same fields auto-update would fill.
 
-Manual clipboard updates always replace generated audio in both the expression audio field and sentence audio field, even when `ankiConnect.behavior.overwriteAudio` is disabled. The manual flow assumes you are intentionally replacing the proxy-generated clip on the newest card.
+Manual clipboard updates always replace generated sentence audio, even when `ankiConnect.behavior.overwriteAudio` is disabled. The word audio field is left unchanged because the word itself does not change in this flow.
 
 This is useful when auto-update is disabled or when you want explicit control over which subtitle line gets attached to the card.