refactor(editor): migrate to Milkdown with LaTeX support and clean up legacy code

- Removed old contenteditable-based MarkdownEditor component
- Integrated Milkdown Crepe with LaTeX (KaTeX) rendering support
- Simplified inline suggestion plugin using ProseMirror decorations
- Removed debug logging and unused components (HelloWorld, plan files)
- Increased debounce from 150ms to 500ms for better performance
- Fixed SSE JSON serialization in backend main.py

src/utils/api.js

@@ -1,52 +1,30 @@
-import { DEBUG, API_URL } from './config.js'
+export async function fetchSuggestion(prefix, suffix, apiUrl = 'http://localhost:8000/v1/completions') {
+  const res = await fetch(apiUrl, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ prefix, suffix, languageId: 'markdown' }),
+  })
 
-export async function fetchSuggestion(prefix, suffix, apiUrl = API_URL) {
-    if (DEBUG) console.log('[Debug] fetchSuggestion called with prefix length:', prefix.length, 'suffix length:', suffix.length)
-    try {
-        const res = await fetch(apiUrl, {
-            method: 'POST',
-            headers: { 'Content-Type': 'application/json' },
-            body: JSON.stringify({ prefix, suffix, languageId: 'markdown' }),
-        })
+  if (!res.ok) {
+    throw new Error(`HTTP ${res.status}`)
+  }
 
-        if (DEBUG) console.log('[Debug] fetchSuggestion response status:', res.status)
-        if (!res.ok) {
-            const errorText = await res.text()
-            throw new Error(`HTTP ${res.status}: ${errorText}`)
-        }
+  const reader = res.body?.getReader()
+  if (!reader) throw new Error('No reader available')
 
-        const reader = res.body?.getReader()
-        if (!reader) {
-            if (DEBUG) console.log('[Debug] No reader available')
-            throw new Error('No reader available')
-        }
-
-        let text = ''
-        while (true) {
-            const { done, value } = await reader.read()
-            if (done) break
-            const chunk = new TextDecoder().decode(value)
-            if (DEBUG) console.log('[Debug] Received chunk:', chunk.substring(0, 100))
-            
-            const lines = chunk.split('\n').filter(l => l.startsWith('data: '))
-            for (const line of lines) {
-                try {
-                    const data = JSON.parse(line.slice(6))
-                    if (data.content) {
-                        text += data.content
-                        if (DEBUG) console.log('[Debug] Added content:', data.content)
-                    }
-                    if (data.done || data.error) break
-                } catch (e) {
-                    if (DEBUG) console.warn('[Debug] JSON parse error:', e)
-                }
-            }
-        }
-        
-        if (DEBUG) console.log('[Debug] Final suggestion text:', text.substring(0, 100))
-        return text
-    } catch (e) {
-        if (DEBUG) console.error('[Debug] fetchSuggestion error:', e)
-        throw e
+  let text = ''
+  while (true) {
+    const { done, value } = await reader.read()
+    if (done) break
+    const chunk = new TextDecoder().decode(value)
+    const lines = chunk.split('\n').filter(l => l.startsWith('data: '))
+    for (const line of lines) {
+      try {
+        const data = JSON.parse(line.slice(6))
+        if (data.content) text += data.content
+        if (data.done || data.error) break
+      } catch (e) {}
     }
+  }
+  return text
 }