feat: add semantic-release for automated versioning and help dialog

- Set up semantic-release with zero-touch CI pipeline on push to main
- Add version sync script to keep all package.json files and APP_VERSION
  constant in sync automatically
- Consolidate Docker publishing into single tag-triggered workflow that
  pushes to both Docker Hub and ghcr.io with semver tags
- Add help dialog with keyboard shortcuts, getting started guide, and
  resource links
- Sync all versions to 0.2.1 to match Docker Hub latest

packages/ai/src/background-removal.ts

@@ -1,6 +1,8 @@
 import { runPythonScript } from "./bridge.js";
-import { writeFile, readFile } from "node:fs/promises";
+import { writeFile, readFile, unlink } from "node:fs/promises";
 import { join } from "node:path";
+import { tmpdir } from "node:os";
+import { randomUUID } from "node:crypto";
 
 export interface RemoveBackgroundOptions {
   model?: string;
@@ -12,22 +14,30 @@ export async function removeBackground(
   outputDir: string,
   options: RemoveBackgroundOptions = {},
 ): Promise<Buffer> {
-  const inputPath = join(outputDir, "input_bg.png");
-  const outputPath = join(outputDir, "output_bg.png");
+  const id = randomUUID();
+  const inputPath = join(tmpdir(), `rembg_in_${id}.png`);
+  const outputPath = join(outputDir, `rembg_out_${id}.png`);
 
   await writeFile(inputPath, inputBuffer);
-  // BiRefNet models need longer timeout (up to 10 min for first load)
-  const timeout = options.model?.startsWith("birefnet") ? 600000 : 300000;
-  const { stdout } = await runPythonScript("remove_bg.py", [
-    inputPath,
-    outputPath,
-    JSON.stringify(options),
-  ], timeout);
+  try {
+    // BiRefNet models need longer timeout (up to 10 min for first load)
+    const timeout = options.model?.startsWith("birefnet") ? 600000 : 300000;
+    const { stdout } = await runPythonScript("remove_bg.py", [
+      inputPath,
+      outputPath,
+      JSON.stringify(options),
+    ], timeout);
 
-  const result = JSON.parse(stdout);
-  if (!result.success) {
-    throw new Error(result.error || "Background removal failed");
+    const result = JSON.parse(stdout);
+    if (!result.success) {
+      throw new Error(result.error || "Background removal failed");
+    }
+
+    const outputBuffer = await readFile(outputPath);
+    return outputBuffer;
+  } finally {
+    // Clean up temp files
+    await unlink(inputPath).catch(() => {});
+    await unlink(outputPath).catch(() => {});
   }
-
-  return readFile(outputPath);
 }