fix(editor): load the float responsive rule + test applyAlignment (#145 review)

Review of #157 (Request changes) caught two blockers:

1. DEAD responsive CSS: the `@media (max-width:600px)` float-reset was added to
   `image-resize.module.css`, which is imported NOWHERE — the image container's
   classes come from `common/node-resize.module.css` (via buildResizeClasses).
   So on mobile a floated image kept its px width + float and crushed the text,
   exactly the failure the rule promised to prevent. Moved the rule to
   `common/node-resize.module.css` (the module actually imported by the resize
   node views); its `:global([data-image-align=...])` selectors are data-attr
   based, so they work unchanged. Reverted the dead addition from the (pre-existing,
   orphaned) image-resize.module.css.

2. `applyAlignment` was untested. Exported it and added `image.spec.ts` (vitest/
   jsdom) covering all five align values, the data-image-align mirror, and the
   floatLeft -> left reset-then-apply (the guard against a leaked float).
   Switched the float writes to the canonical CSSOM `cssFloat` property (portable:
   browsers + jsdom; behavior identical to the `.float` alias).

editor-ext build + client tsc clean; 6 image.spec tests green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/editor-ext/src/lib/image/image.spec.ts

@@ -0,0 +1,67 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import { applyAlignment } from "./image";
+
+// applyAlignment is a pure DOM mutation: it sets the float / padding /
+// justify-content / data-image-align on an image node-view container per the
+// resolved `align`. Tested directly (issue #145 review) since the five-way
+// branch, the reset-then-apply guard, and the data-image-align mirror (which the
+// responsive @media rule keys off) are otherwise uncovered.
+
+describe("applyAlignment", () => {
+  let el: HTMLElement;
+  beforeEach(() => {
+    el = document.createElement("div");
+  });
+
+  it("floatLeft -> float:left + right padding, mirrored on data-image-align", () => {
+    applyAlignment(el, "floatLeft");
+    expect(el.style.cssFloat).toBe("left");
+    expect(el.style.padding).toBe("0px 10px 0px 0px");
+    expect(el.dataset.imageAlign).toBe("floatLeft");
+    expect(el.style.justifyContent).toBe("flex-start");
+  });
+
+  it("floatRight -> float:right + left padding", () => {
+    applyAlignment(el, "floatRight");
+    expect(el.style.cssFloat).toBe("right");
+    expect(el.style.padding).toBe("0px 0px 0px 10px");
+    expect(el.dataset.imageAlign).toBe("floatRight");
+    expect(el.style.justifyContent).toBe("flex-end");
+  });
+
+  it("left -> justify flex-start, no float", () => {
+    applyAlignment(el, "left");
+    expect(el.style.justifyContent).toBe("flex-start");
+    expect(el.style.cssFloat).toBe("");
+    expect(el.style.padding).toBe("");
+    expect(el.dataset.imageAlign).toBe("left");
+  });
+
+  it("right -> justify flex-end, no float", () => {
+    applyAlignment(el, "right");
+    expect(el.style.justifyContent).toBe("flex-end");
+    expect(el.style.cssFloat).toBe("");
+    expect(el.dataset.imageAlign).toBe("right");
+  });
+
+  it("center (default) -> justify center, no float", () => {
+    applyAlignment(el, "center");
+    expect(el.style.justifyContent).toBe("center");
+    expect(el.style.cssFloat).toBe("");
+    expect(el.style.padding).toBe("");
+    expect(el.dataset.imageAlign).toBe("center");
+  });
+
+  it("clears a previous float when switching floatLeft -> left (reset-then-apply)", () => {
+    applyAlignment(el, "floatLeft");
+    expect(el.style.cssFloat).toBe("left");
+    expect(el.style.padding).toBe("0px 10px 0px 0px");
+    // Switching to a block alignment must drop the float and its padding, not
+    // leak them (the bug the reset guard prevents).
+    applyAlignment(el, "left");
+    expect(el.style.cssFloat).toBe("");
+    expect(el.style.padding).toBe("");
+    expect(el.dataset.imageAlign).toBe("left");
+    expect(el.style.justifyContent).toBe("flex-start");
+  });
+});

packages/editor-ext/src/lib/image/image.ts

@@ -376,10 +376,10 @@ export const TiptapImage = Image.extend<ImageOptions>({
   },
 });
 
-function applyAlignment(container: HTMLElement, align: string) {
+export function applyAlignment(container: HTMLElement, align: string) {
   // Reset the float-mode styles first so toggling between any two modes is clean
   // (a previous float must not leak into a later left/center/right).
-  container.style.float = "";
+  container.style.cssFloat = "";
   container.style.padding = "";
   // Mirror the resolved alignment onto the CONTAINER as a data attribute so the
   // responsive stylesheet can neutralize the float on small screens (an inline
@@ -389,11 +389,11 @@ function applyAlignment(container: HTMLElement, align: string) {
   if (align === "floatLeft") {
     // Real text wrap: the (shrink-to-fit) container floats left, text flows on
     // its right. The inner <img> already carries max-width:100%.
-    container.style.float = "left";
+    container.style.cssFloat = "left";
     container.style.padding = "0 10px 0 0";
     container.style.justifyContent = "flex-start";
   } else if (align === "floatRight") {
-    container.style.float = "right";
+    container.style.cssFloat = "right";
     container.style.padding = "0 0 0 10px";
     container.style.justifyContent = "flex-end";
   } else if (align === "left") {