feat(overlay): add in-app changelog modal (#187)

src/main/runtime/changelog/bundled-changelog.ts

@@ -0,0 +1,35 @@
+export function resolveBundledChangelogPath(deps: {
+  resourcesPath: string;
+  appPath: string;
+  dirname: string;
+  joinPath: (...parts: string[]) => string;
+  fileExists: (path: string) => boolean;
+}): string | null {
+  const candidates = [
+    deps.joinPath(deps.resourcesPath, 'CHANGELOG.md'),
+    deps.joinPath(deps.appPath, 'CHANGELOG.md'),
+    deps.joinPath(deps.dirname, '..', 'CHANGELOG.md'),
+    deps.joinPath(deps.dirname, '..', '..', 'CHANGELOG.md'),
+  ];
+
+  return candidates.find((candidate) => deps.fileExists(candidate)) ?? null;
+}
+
+export function readBundledChangelog(deps: {
+  resolvePath: () => string | null;
+  readFile: (path: string) => string;
+  logWarn: (message: string) => void;
+}): string | null {
+  const changelogPath = deps.resolvePath();
+  if (!changelogPath) return null;
+  try {
+    return deps.readFile(changelogPath);
+  } catch (error) {
+    deps.logWarn(
+      `Failed to read bundled changelog at ${changelogPath}: ${
+        error instanceof Error ? error.message : String(error)
+      }`,
+    );
+    return null;
+  }
+}