fix(frontend): Attempt to resolve TypeError in RichTextInput.svelte

Fixes an issue where `ue.getWordAtDocPos is not a function` would be thrown in `MessageInput.svelte`.

The error was caused by a timing issue where the `getWordAtDocPos` method on the `RichTextInput` component was not available when called from an event handler within the same component.

This change refactors the code to pass the `getWordAtDocPos` function as a callback prop from `RichTextInput` to `MessageInput`, ensuring it's available when needed.

src/lib/utils/marked/katex-extension.ts

@@ -23,8 +23,8 @@ const ALLOWED_SURROUNDING_CHARS =
 // const inlineRule = /^(\${1,2})(?!\$)((?:\\.|[^\\\n])*?(?:\\.|[^\\\n\$]))\1(?=[\s?!\.,:？！。，：]|$)/;
 // const blockRule = /^(\${1,2})\n((?:\\[^]|[^\\])+?)\n\1(?:\n|$)/;
 
-let inlinePatterns = [];
-let blockPatterns = [];
+const inlinePatterns = [];
+const blockPatterns = [];
 
 function escapeRegex(string) {
 	return string.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
@@ -69,7 +69,7 @@ export default function (options = {}) {
 }
 
 function katexStart(src, displayMode: boolean) {
-	let ruleReg = displayMode ? blockRule : inlineRule;
+	const ruleReg = displayMode ? blockRule : inlineRule;
 
 	let indexSrc = src;
 
@@ -78,7 +78,7 @@ function katexStart(src, displayMode: boolean) {
 		let startIndex = -1;
 		let startDelimiter = '';
 		let endDelimiter = '';
-		for (let delimiter of DELIMITER_LIST) {
+		for (const delimiter of DELIMITER_LIST) {
 			if (delimiter.display !== displayMode) {
 				continue;
 			}
@@ -115,8 +115,8 @@ function katexStart(src, displayMode: boolean) {
 }
 
 function katexTokenizer(src, tokens, displayMode: boolean) {
-	let ruleReg = displayMode ? blockRule : inlineRule;
-	let type = displayMode ? 'blockKatex' : 'inlineKatex';
+	const ruleReg = displayMode ? blockRule : inlineRule;
+	const type = displayMode ? 'blockKatex' : 'inlineKatex';
 
 	const match = src.match(ruleReg);