fix(markdown): preserve encoded image paths after rebase

Keep the shared renderer image normalization and file-read regression coverage that originally lived in the main integration merge.

packages/app/src/components/markdown/image-source.test.ts

@@ -1,4 +1,9 @@
-import { describe, expect, it } from "vitest";
+import { mkdir, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { prepareMarkdownSource } from "./source";
+import { resolveAssistantImageSource } from "@/utils/assistant-image-source";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
 
 import { resolveMarkdownFileDirectory, resolveMarkdownPreviewImageSource } from "./image-source";
 
@@ -163,3 +168,52 @@ describe("resolveMarkdownPreviewImageSource", () => {
     ).toBe("C:/Users/test/repo/images/hero.png");
   });
 });
+
+describe("local assistant Markdown images", () => {
+  let workspaceRoot: string;
+  const imageBytes = Buffer.from(
+    "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8DwHwAFBQIAX8jx0gAAAABJRU5ErkJggg==",
+    "base64",
+  );
+
+  beforeEach(async () => {
+    workspaceRoot = await mkdtemp(path.join(os.tmpdir(), "assistant-markdown-image-"));
+    await mkdir(path.join(workspaceRoot, "My Apps", "Мои"), { recursive: true });
+    await writeFile(path.join(workspaceRoot, "My Apps", "Мои", "test.png"), imageBytes);
+    await writeFile(path.join(workspaceRoot, "literal%20name.png"), imageBytes);
+  });
+
+  afterEach(async () => {
+    await rm(workspaceRoot, { recursive: true, force: true });
+  });
+
+  it.each([
+    "absolute angle",
+    "absolute encoded",
+    "relative angle",
+    "relative encoded",
+    "file URI",
+    "literal percent",
+  ])("reads the actual image for the %s destination", async (form) => {
+    const absolute = path.join(workspaceRoot, "My Apps", "Мои", "test.png");
+    const destinations: Record<string, string> = {
+      "absolute angle": `<${absolute}>`,
+      "absolute encoded": encodeURI(absolute),
+      "relative angle": "<My Apps/Мои/test.png>",
+      "relative encoded": encodeURI("My Apps/Мои/test.png"),
+      "file URI": `file://${encodeURI(absolute)}`,
+      "literal percent": `${workspaceRoot}/literal%2520name.png`,
+    };
+    const prepared = prepareMarkdownSource(`![test](${destinations[form]})`);
+    expect(prepared.images).toHaveLength(1);
+    const source = resolveMarkdownPreviewImageSource({
+      source: prepared.images[0]!.source,
+      markdownPath: "",
+      workspaceRoot,
+    })!;
+    const target = resolveAssistantImageSource({ source, workspaceRoot });
+    expect(target?.kind).toBe("file_rpc");
+    if (target?.kind !== "file_rpc") throw new Error("Expected a local image read target");
+    await expect(readFile(path.resolve(target.cwd, target.path))).resolves.toEqual(imageBytes);
+  });
+});

packages/app/src/components/markdown/images.ts

@@ -40,13 +40,11 @@ export function useMarkdownSource(text: string, context: MarkdownImageContext) {
   );
   const sources = [...new Set(prepared.images.map((image) => image.source))];
   const acquisitions = sources.map((source) => {
-    const resolved = context.filePath
-      ? resolveMarkdownPreviewImageSource({
-          source,
-          markdownPath: context.filePath,
-          workspaceRoot: context.workspaceRoot,
-        })
-      : source;
+    const resolved = resolveMarkdownPreviewImageSource({
+      source,
+      markdownPath: context.filePath ?? "",
+      workspaceRoot: context.workspaceRoot,
+    });
     return createAssistantImageFileAcquisition({
       port: context.client
         ? {