refactor: remove FFmpeg dependencies and related video processing logic

- Deleted FFmpeg related packages from package.json and package-lock.json.
- Removed video transcoding and editing functionalities from FileContent.vue.
- Simplified video handling logic and error management in FileContent.vue.
- Added a clear button in MilkdownEditor.vue for clearing the editor content.
- Enhanced UniverPreview.vue to clear detached popups and mount nodes on destroy.
- Updated docBlockPlugin.ts to improve context handling for document blocks.
- Cleaned up vite.config.js by removing cross-origin isolation headers.

src/plugins/docBlockPlugin.ts

@@ -18,6 +18,8 @@ import {
 
 const FALLBACK_BLOCK_SEPARATOR = '\n\n'
 const FALLBACK_LEAF_TEXT = '\n'
+const CONTEXT_SEPARATOR = '\n\n'
+const MAX_SUFFIX_RATIO = 0.35
 
 function serializeRangeToMarkdown(
   doc: ProseNode,
@@ -33,6 +35,75 @@ function serializeRangeToMarkdown(
   return sliceDoc ? serializer(sliceDoc) : doc.textBetween(from, to, FALLBACK_BLOCK_SEPARATOR, FALLBACK_LEAF_TEXT)
 }
 
+function getJoinedLength(parts: string[]) {
+  let total = 0
+  let hasContent = false
+  for (const part of parts) {
+    if (!part) continue
+    if (hasContent) total += CONTEXT_SEPARATOR.length
+    total += part.length
+    hasContent = true
+  }
+  return total
+}
+
+function takeTail(text: string, limit: number) {
+  if (!text || limit <= 0) return ''
+  if (text.length <= limit) return text
+  return text.slice(-limit)
+}
+
+function takeHead(text: string, limit: number) {
+  if (!text || limit <= 0) return ''
+  if (text.length <= limit) return text
+  return text.slice(0, limit)
+}
+
+function fitPrefixSections(parts: string[], limit: number) {
+  if (limit <= 0) return ''
+
+  const fitted: string[] = []
+  let remaining = limit
+
+  for (let index = parts.length - 1; index >= 0; index -= 1) {
+    const part = parts[index]
+    if (!part || remaining <= 0) continue
+
+    const separatorCost = fitted.length > 0 ? CONTEXT_SEPARATOR.length : 0
+    if (remaining <= separatorCost) break
+
+    const nextPart = takeTail(part, remaining - separatorCost)
+    if (!nextPart) continue
+
+    fitted.unshift(nextPart)
+    remaining -= nextPart.length + separatorCost
+  }
+
+  return fitted.join(CONTEXT_SEPARATOR)
+}
+
+function fitSuffixSections(parts: string[], limit: number) {
+  if (limit <= 0) return ''
+
+  const fitted: string[] = []
+  let remaining = limit
+
+  for (const part of parts) {
+    if (!part || remaining <= 0) continue
+
+    const separatorCost = fitted.length > 0 ? CONTEXT_SEPARATOR.length : 0
+    if (remaining <= separatorCost) break
+
+    const nextPart = takeHead(part, remaining - separatorCost)
+    if (!nextPart) continue
+
+    fitted.push(nextPart)
+    remaining -= nextPart.length + separatorCost
+  }
+
+  return fitted.join(CONTEXT_SEPARATOR)
+}
+
 function buildDocContext(doc: ProseNode, excludePos?: number) {
   const blocks: string[] = []
   doc.descendants((node, pos) => {
@@ -112,16 +183,37 @@ class DocBlockNodeView implements NodeView {
     const before = stripDocBlockMarkdown(serializeRangeToMarkdown(doc, 0, pos, schema, this.serializer))
     const after = stripDocBlockMarkdown(serializeRangeToMarkdown(doc, pos + this.node.nodeSize, doc.content.size, schema, this.serializer))
     const docContext = buildDocContext(doc, pos)
-    const mergedPrefix = [docContext, before, payload.prefix].filter(Boolean).join('\n\n')
-    const mergedSuffix = [payload.suffix, after].filter(Boolean).join('\n\n')
+    const prefixParts = [docContext, before, payload.prefix].filter(Boolean)
+    const suffixParts = [payload.suffix, after].filter(Boolean)
+    const mergedPrefix = prefixParts.join(CONTEXT_SEPARATOR)
+    const mergedSuffix = suffixParts.join(CONTEXT_SEPARATOR)
+
     if (mergedPrefix.length + mergedSuffix.length > DOC_CONTEXT_LIMIT) {
+      const prefixCapacity = getJoinedLength(prefixParts)
+      const suffixCapacity = getJoinedLength(suffixParts)
+      const maxSuffixBudget = Math.min(suffixCapacity, Math.floor(DOC_CONTEXT_LIMIT * MAX_SUFFIX_RATIO))
+
+      let suffixBudget = maxSuffixBudget
+      let prefixBudget = DOC_CONTEXT_LIMIT - suffixBudget
+
+      if (prefixCapacity < prefixBudget) {
+        const transferable = prefixBudget - prefixCapacity
+        suffixBudget = Math.min(suffixCapacity, suffixBudget + transferable)
+        prefixBudget = DOC_CONTEXT_LIMIT - suffixBudget
+      } else if (suffixCapacity < suffixBudget) {
+        const transferable = suffixBudget - suffixCapacity
+        prefixBudget = Math.min(prefixCapacity, prefixBudget + transferable)
+        suffixBudget = DOC_CONTEXT_LIMIT - prefixBudget
+      }
+
       return {
-        prefix: mergedPrefix.slice(0, DOC_CONTEXT_LIMIT),
-        suffix: '',
+        prefix: fitPrefixSections(prefixParts, prefixBudget),
+        suffix: fitSuffixSections(suffixParts, suffixBudget),
         languageId: payload.languageId,
-        blocked: true,
+        blocked: false,
       }
     }
+
     return {
       prefix: mergedPrefix,
       suffix: mergedSuffix,