feat(server): edit tool intent collect (#12998)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Footnotes are now included in streamed AI responses, formatted as
markdown and appended at the end of the output when available.

* **Improvements**
* Enhanced handling of footnotes across multiple AI providers, ensuring
consistent display of additional information after the main response.

* **Refactor**
  * Removed citation parsing from one provider to streamline output.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/providers/utils.ts

@@ -412,6 +412,10 @@ export function toError(error: unknown): Error {
   }
 }
 
+type DocEditFootnote = {
+  intent: string;
+  result: string;
+};
 export class TextStreamParser {
   private readonly logger = new Logger(TextStreamParser.name);
   private readonly CALLOUT_PREFIX = '\n[!]\n';
@@ -420,6 +424,8 @@ export class TextStreamParser {
 
   private prefix: string | null = this.CALLOUT_PREFIX;
 
+  private readonly docEditFootnotes: DocEditFootnote[] = [];
+
   public parse(chunk: TextStreamPart<CustomAITools>) {
     let result = '';
     switch (chunk.type) {
@@ -463,6 +469,13 @@ export class TextStreamParser {
             result += `\nWriting document "${chunk.args.title}"\n`;
             break;
           }
+          case 'doc_edit': {
+            this.docEditFootnotes.push({
+              intent: chunk.args.instructions,
+              result: '',
+            });
+            break;
+          }
         }
         result = this.markAsCallout(result);
         break;
@@ -476,6 +489,10 @@ export class TextStreamParser {
           case 'doc_edit': {
             if (chunk.result && typeof chunk.result === 'object') {
               result += `\n${chunk.result.result}\n`;
+              this.docEditFootnotes[this.docEditFootnotes.length - 1].result =
+                chunk.result.result;
+            } else {
+              this.docEditFootnotes.pop();
             }
             break;
           }
@@ -520,6 +537,13 @@ export class TextStreamParser {
     return result;
   }
 
+  public end() {
+    const footnotes = this.docEditFootnotes.map((footnote, index) => {
+      return `[^edit${index + 1}]: ${JSON.stringify({ type: 'doc-edit', ...footnote })}`;
+    });
+    return footnotes.join('\n');
+  }
+
   private addPrefix(text: string) {
     if (this.prefix) {
       const result = this.prefix + text;