fix: QA sweep -- SSE crash, memory leaks, HEIC Docker decode, TGA detection, lint cleanup

- Fix SSE write-after-end crash in progress.ts (remove callback before ending stream)
- Fix blob URL memory leaks: revoke processedPreviewUrl and old HEIC preview URLs
- Add AbortController to batch fetch in use-tool-processor and use-pipeline-processor
- Fix TGA format misidentified as CUR (extension overrides magic bytes)
- Add libheif-plugin-libde265 to Docker for HEIC/HEIF decode support
- Remove unused imports and state (AppLayout, setSampledColor, useEffect)
- Fix non-null assertions in meme-text-renderer and meme-generator
- Fix confusing void type in meme-templates
- Remove unnecessary useEffect deps in adjustments-panel
- Fix Playwright strict mode violations in 5 E2E tests

tests/e2e/gui-performance.spec.ts

@@ -554,8 +554,8 @@ test.describe("File Upload Preview Timing", () => {
     await expect(
       page
         .getByText(/test-image/i)
-        .first()
-        .or(page.locator("img[src^='blob:']").first()),
+        .or(page.locator("img[src^='blob:']"))
+        .first(),
     ).toBeVisible({ timeout: 5_000 });
     const previewTime = Date.now() - start;
 

tests/e2e/gui-tools-ai.spec.ts

@@ -1078,8 +1078,8 @@ test.describe("GUI AI Tools", () => {
       await expect(
         page
           .getByText(/upload/i)
-          .first()
-          .or(page.locator("img").first()),
+          .or(page.locator("img"))
+          .first(),
       ).toBeVisible({ timeout: 10_000 });
     });
   });

tests/e2e/gui-tools-layout.spec.ts

@@ -209,7 +209,7 @@ test.describe("GUI Layout Tools", () => {
     test("shows Background section with tabs", async ({ loggedInPage: page }) => {
       await page.goto("/beautify");
 
-      await expect(page.getByText("Background")).toBeVisible();
+      await expect(page.getByText("Background").first()).toBeVisible();
       await expect(page.getByRole("button", { name: "Gradient" })).toBeVisible();
       await expect(page.getByRole("button", { name: "Solid" })).toBeVisible();
       await expect(page.getByRole("button", { name: "Image" })).toBeVisible();

tests/e2e/gui-tools-overlay.spec.ts

@@ -256,7 +256,7 @@ test.describe("GUI Watermark & Overlay Tools", () => {
     test("shows overlay image upload button", async ({ loggedInPage: page }) => {
       await page.goto("/compose");
 
-      await expect(page.getByText("Overlay Image")).toBeVisible();
+      await expect(page.getByText("Overlay Image").first()).toBeVisible();
       await expect(page.getByText("Choose overlay image")).toBeVisible();
     });
 

tests/e2e/gui-tools-utility.spec.ts

@@ -27,7 +27,7 @@ test.describe("GUI Utility Tools", () => {
     test("shows second image upload button with correct label", async ({ loggedInPage: page }) => {
       await page.goto("/compare");
 
-      await expect(page.getByText("Second Image")).toBeVisible();
+      await expect(page.getByText("Second Image").first()).toBeVisible();
       await expect(page.getByText("Choose second image")).toBeVisible();
     });