fix(ui): route default resets through removal

ui/src/components/config-form-collection-defaults.browser.test.ts

@@ -194,6 +194,7 @@ describe("config form collection defaults", () => {
   it("shows and restores a top-level object default without nesting the section", () => {
     const container = document.createElement("div");
     const onPatch = vi.fn();
+    const onRemove = vi.fn();
     const schema = {
       type: "object" as const,
       title: "Settings",
@@ -213,6 +214,7 @@ describe("config form collection defaults", () => {
           unsupported: new Set(),
           disabled: false,
           onPatch,
+          onRemove,
         },
         renderNode,
       ),
@@ -222,9 +224,11 @@ describe("config form collection defaults", () => {
     expect(container.textContent).toContain('Default: {"mode":"balanced"}');
     expect(container.querySelector("details")).toBeNull();
     resetButton(container).click();
-    expect(onPatch).toHaveBeenCalledWith(["settings"], undefined);
+    expect(onRemove).toHaveBeenCalledWith(["settings"]);
+    expect(onPatch).not.toHaveBeenCalled();
 
     onPatch.mockClear();
+    onRemove.mockClear();
     render(
       renderObject(
         {
@@ -235,6 +239,7 @@ describe("config form collection defaults", () => {
           unsupported: new Set(),
           disabled: false,
           onPatch,
+          onRemove,
         },
         renderNode,
       ),
@@ -249,6 +254,7 @@ describe("config form collection defaults", () => {
         .placeholder,
     ).toBe("Default: balanced");
     expect(onPatch).not.toHaveBeenCalled();
+    expect(onRemove).not.toHaveBeenCalled();
   });
 
   it("conceals a sensitive top-level object default", () => {

ui/src/components/config-form-scalar-integrity.browser.test.ts

@@ -231,9 +231,10 @@ describe("config form scalar integrity", () => {
       container.querySelector<HTMLButtonElement>("button[aria-label='Reset to default']"),
       "number reset",
     ).click();
-    expect(onPatch).toHaveBeenCalledWith(["retries"], undefined);
-    expect(onRemove).not.toHaveBeenCalled();
+    expect(onRemove).toHaveBeenCalledWith(["retries"]);
+    expect(onPatch).not.toHaveBeenCalled();
 
+    onRemove.mockClear();
     render(
       renderSelect({
         schema: { type: "string", default: "balanced" },
@@ -257,7 +258,8 @@ describe("config form scalar integrity", () => {
     expect(select.selectedOptions[0]?.textContent?.trim()).toBe("fast");
     select.value = "__unset__";
     select.dispatchEvent(new Event("change", { bubbles: true }));
-    expect(onPatch).toHaveBeenCalledWith(["mode"], undefined);
+    expect(onRemove).toHaveBeenCalledWith(["mode"]);
+    expect(onPatch).not.toHaveBeenCalled();
 
     render(
       renderSelect({

ui/src/components/config-form.node.scalar.ts

@@ -494,7 +494,9 @@ export function renderSelect(
           const accepted =
             params.isRequired && schema.default !== undefined
               ? onPatch(path, structuredClone(schema.default))
-              : onPatch(path, undefined);
+              : params.onRemove
+                ? params.onRemove(path)
+                : onPatch(path, undefined);
           if (accepted === false) {
             target.value = selectedValue;
           }

ui/src/components/config-form.node.shared.ts

@@ -286,7 +286,7 @@ export function renderSchemaDefaultDescription(
 export function renderRestoreDefaultButton(
   params: Pick<
     ConfigNodeRenderParams,
-    "schema" | "value" | "path" | "disabled" | "isRequired" | "onPatch"
+    "schema" | "value" | "path" | "disabled" | "isRequired" | "onPatch" | "onRemove"
   >,
 ): TemplateResult | typeof nothing {
   if (params.schema.default === undefined || params.value === undefined) {
@@ -305,6 +305,10 @@ export function renderRestoreDefaultButton(
             params.onPatch(params.path, structuredClone(params.schema.default));
             return;
           }
+          if (params.onRemove) {
+            params.onRemove(params.path);
+            return;
+          }
           params.onPatch(params.path, undefined);
         }}
       >