feat(layout): plan 03 — frontend plugin ABI + handshake + load lifecycle

2 files changed, 100 insertions, 0 deletions

diff --git a/src/features/layout/logic/registry.test.ts b/src/features/layout/logic/registry.test.ts
index 443e50d..e5e947c 100644
--- a/src/features/layout/logic/registry.test.ts
+++ b/src/features/layout/logic/registry.test.ts
@@ -4,8 +4,10 @@ import {
   getView,
   listPanelViews,
   listViews,
+  registerPluginView,
   registerView,
   unregisterView,
+  unregisterViewsByPlugin,
   type ViewRegistration,
   viewRegistry,
 } from "./registry";
@@ -78,3 +80,69 @@ describe("view registry", () => {
     expect(ids.indexOf("z-first")).toBeLessThan(ids.indexOf("a-second"));
   });
 });
+
+// ── Plugin-view registration (plan 03) — forced attribution + the sweep ─────
+
+describe("registerPluginView / unregisterViewsByPlugin (plan 03)", () => {
+  it("forces the importing plugin's pluginId attribution", () => {
+    const dispose = registerPluginView(
+      { id: "abi-view", label: "ABI View", component: fakeComponent },
+      "my-plugin",
+    );
+    expect(getView("abi-view")?.pluginId).toBe("my-plugin");
+    dispose();
+    expect(getView("abi-view")).toBeUndefined();
+  });
+
+  it("returns a working per-view disposer (the plugin deactivate contract)", () => {
+    const dispose = registerPluginView(
+      { id: "abi-view-2", label: "ABI View", component: fakeComponent },
+      "my-plugin",
+    );
+    dispose();
+    dispose(); // idempotent
+    expect(getView("abi-view-2")).toBeUndefined();
+  });
+
+  it("the sweep removes exactly that plugin's views (registry attribution)", () => {
+    registerPluginView({ id: "p1-a", label: "A", component: fakeComponent }, "plugin-1");
+    registerPluginView({ id: "p1-b", label: "B", component: fakeComponent }, "plugin-1");
+    registerPluginView({ id: "p2-a", label: "C", component: fakeComponent }, "plugin-2");
+    registerView(registration({ id: "builtin" })); // no pluginId — never swept
+
+    unregisterViewsByPlugin("plugin-1");
+    expect(getView("p1-a")).toBeUndefined();
+    expect(getView("p1-b")).toBeUndefined();
+    expect(getView("p2-a")).not.toBeUndefined();
+    expect(getView("builtin")).not.toBeUndefined();
+
+    unregisterViewsByPlugin("plugin-2");
+    expect(getView("p2-a")).toBeUndefined();
+    expect(getView("builtin")).not.toBeUndefined();
+  });
+
+  it("the sweep is idempotent and a no-op for an unknown plugin", () => {
+    unregisterViewsByPlugin("nobody");
+    registerPluginView({ id: "p3-a", label: "A", component: fakeComponent }, "plugin-3");
+    unregisterViewsByPlugin("plugin-3");
+    expect(() => unregisterViewsByPlugin("plugin-3")).not.toThrow();
+  });
+
+  it("a duplicate id from a plugin throws LOUDLY (the driver marks it failed)", () => {
+    registerView(registration({ id: "taken" }));
+    expect(() =>
+      registerPluginView({ id: "taken", label: "Taken", component: fakeComponent }, "my-plugin"),
+    ).toThrow(/duplicate view id/);
+  });
+
+  it("sweep removals are visible to registry subscribers (reactive)", () => {
+    const seen: string[][] = [];
+    const unsubscribe = viewRegistry.subscribe((views) => {
+      seen.push(views.map((v) => v.id));
+    });
+    registerPluginView({ id: "reactive", label: "R", component: fakeComponent }, "p");
+    unregisterViewsByPlugin("p");
+    unsubscribe();
+    expect(seen.at(-1)).not.toContain("reactive");
+  });
+});
diff --git a/src/features/layout/logic/registry.ts b/src/features/layout/logic/registry.ts
index b072d2f..3a86cb9 100644
--- a/src/features/layout/logic/registry.ts
+++ b/src/features/layout/logic/registry.ts
@@ -82,6 +82,38 @@ export function unregisterView(id: string): void {
   if (byId.delete(id)) publish();
 }
 
+/**
+ * Register a PLUGIN view (plan 03) — the ABI-facing registration: the
+ * `pluginId` attribution is FORCED to the importing plugin (plugins cannot
+ * attribute views to another plugin or to no plugin), which is what makes
+ * `unregisterViewsByPlugin`'s unload sweep exact. Returns the per-view
+ * disposer (the plugin's deactivate contract). A duplicate id throws
+ * LOUDLY — the driver catches it and marks the plugin's FE half failed.
+ */
+export function registerPluginView(
+  registration: Omit<ViewRegistration, "pluginId">,
+  pluginId: string,
+): () => void {
+  registerView({ ...registration, pluginId });
+  return () => unregisterView(registration.id);
+}
+
+/**
+ * Remove every view attributed to one plugin (the plan-03 unload sweep).
+ * Idempotent; the reactive registry re-renders open dropdowns, and tiles
+ * holding removed views fall back to `FallbackTile` (never a crash).
+ */
+export function unregisterViewsByPlugin(pluginId: string): void {
+  let changed = false;
+  for (const [id, view] of byId) {
+    if (view.pluginId === pluginId) {
+      byId.delete(id);
+      changed = true;
+    }
+  }
+  if (changed) publish();
+}
+
 /** Look a view up by id (undefined → the renderer shows its fallback tile). */
 export function getView(id: string): RegisteredView | undefined {
   return byId.get(id);