fix lsp diagnostic accurancy

packages/opencode/src/file/index.ts

@@ -1,5 +1,8 @@
 import { z } from "zod"
 import { Bus } from "../bus"
+import { $ } from "bun"
+import { createPatch } from "diff"
+import path from "path"
 
 export namespace File {
   export const Event = {
@@ -10,4 +13,26 @@ export namespace File {
       }),
     ),
   }
+
+  export async function read(file: string) {
+    const content = await Bun.file(file).text()
+    const gitDiff = await $`git diff HEAD -- ${file}`
+      .cwd(path.dirname(file))
+      .quiet()
+      .nothrow()
+      .text()
+    if (gitDiff.trim()) {
+      const relativePath = path.relative(process.cwd(), file)
+      const originalContent = await $`git show HEAD:./${relativePath}`
+        .cwd(process.cwd())
+        .quiet()
+        .nothrow()
+        .text()
+      if (originalContent.trim()) {
+        const patch = createPatch(file, originalContent, content)
+        return patch
+      }
+    }
+    return content.trim()
+  }
 }