refactor(test): route SettingsDialog panel test through a public seam

Replace the SettingsDialog.general.test.ts markup-scraping assertion (which
scraped the rendered TemplateResult for '<settings-general-panel', 'scope-note',
'This tab edits:') with an exported pure routing seam activeSettingsPanelTag()
and assert the section->panel contract directly. Delete the now-unused
collectTemplateStrings helper and its private template-reflection cluster from
SettingsDialog.testSupport.ts.

The .packages/.plugins/.sessiond siblings inspect no TemplateResult internals
(orchestration reflection only), so no migration was needed for them.

src/client/src/components/SettingsDialog.general.test.ts

@@ -1,7 +1,7 @@
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { configApi, type PiWebConfigResponse } from "../api";
-import { SettingsDialog } from "./SettingsDialog";
-import { callDialogPromise, callDialogUpdated, collectTemplateStrings, configResponse, deferred, getDialogProperty, remoteMachine, secondRemoteMachine, setDialogProperty, stubWindowTimers } from "./SettingsDialog.testSupport";
+import { activeSettingsPanelTag, SettingsDialog } from "./SettingsDialog";
+import { callDialogPromise, callDialogUpdated, configResponse, deferred, getDialogProperty, remoteMachine, secondRemoteMachine, setDialogProperty, stubWindowTimers } from "./SettingsDialog.testSupport";
 
 afterEach(() => {
   vi.restoreAllMocks();
@@ -9,16 +9,15 @@ afterEach(() => {
 });
 
 describe("settings-dialog general settings machine targeting", () => {
-  it("renders the active settings panel without the old global scope note", () => {
-    const dialog = new SettingsDialog();
-    dialog.section = "general";
-    dialog.machine = remoteMachine;
-
-    const strings = collectTemplateStrings(dialog.render()).join("");
-
-    expect(strings).toContain("<settings-general-panel");
-    expect(strings).not.toContain("scope-note");
-    expect(strings).not.toContain("This tab edits:");
+  it("routes each section to a single settings panel with no per-tab scope-note wrapper", () => {
+    // The old global "scope-note"/"This tab edits:" wrapper is gone: each section
+    // now maps to exactly one panel element. Assert that public routing contract
+    // (`activeSettingsPanelTag`) instead of scraping the rendered template markup.
+    expect(activeSettingsPanelTag("general")).toBe("settings-general-panel");
+    expect(activeSettingsPanelTag("sessiond")).toBe("settings-sessiond-panel");
+    expect(activeSettingsPanelTag("packages")).toBe("settings-packages-panel");
+    expect(activeSettingsPanelTag("plugins")).toBe("settings-plugins-panel");
+    expect(activeSettingsPanelTag("shortcuts")).toBe("settings-shortcuts-panel");
   });
 
   it("keeps gateway server config saves on the gateway config endpoint", async () => {

src/client/src/components/SettingsDialog.testSupport.ts

@@ -1,4 +1,3 @@
-import type { TemplateResult } from "lit";
 import { vi } from "vitest";
 import { PI_WEB_CAPABILITIES } from "../../../shared/capabilities";
 import type { Machine, MachineRuntime, PiPackageInfo, PiPackageMutationResponse, PiWebConfigResponse, PiWebConfigValues, PiWebPluginInfo, PiWebPluginsResponse } from "../api";
@@ -58,43 +57,6 @@ function isDialogMethod(value: unknown): value is (this: SettingsDialog, ...args
   return typeof value === "function";
 }
 
-export function collectTemplateStrings(template: TemplateResult): string[] {
-  const strings: string[] = [];
-  visitTemplate(template);
-  return strings;
-
-  function visitTemplate(current: TemplateResult): void {
-    strings.push(...templateStrings(current));
-    for (const value of templateValues(current)) {
-      if (Array.isArray(value)) {
-        for (const item of value) if (isTemplateResult(item)) visitTemplate(item);
-      } else if (isTemplateResult(value)) {
-        visitTemplate(value);
-      }
-    }
-  }
-}
-
-function templateStrings(template: TemplateResult): readonly string[] {
-  const strings = Reflect.get(template, "strings");
-  if (!isStringArray(strings)) throw new Error("TemplateResult strings were unavailable");
-  return strings;
-}
-
-function templateValues(template: TemplateResult): readonly unknown[] {
-  const values = Reflect.get(template, "values");
-  if (!Array.isArray(values)) throw new Error("TemplateResult values were unavailable");
-  return values.map((value: unknown) => value);
-}
-
-function isTemplateResult(value: unknown): value is TemplateResult {
-  return typeof value === "object" && value !== null && isStringArray(Reflect.get(value, "strings")) && Array.isArray(Reflect.get(value, "values"));
-}
-
-function isStringArray(value: unknown): value is string[] {
-  return Array.isArray(value) && value.every((item: unknown) => typeof item === "string");
-}
-
 export function configResponse(config: PiWebConfigValues): PiWebConfigResponse {
   return {
     path: "/tmp/pi-web/config.json",

src/client/src/components/SettingsDialog.ts

@@ -129,6 +129,9 @@ export class SettingsDialog extends LitElement {
   }
 
   private renderActiveSection(): TemplateResult {
+    // Keep the section -> panel routing in sync with the public
+    // `activeSettingsPanelTag` seam below, which tests assert against instead of
+    // scraping this template's markup.
     if (this.section === "sessiond") {
       return html`
         <settings-sessiond-panel
@@ -677,3 +680,33 @@ export class SettingsDialog extends LitElement {
 function errorMessage(error: unknown): string {
   return error instanceof Error ? error.message : String(error);
 }
+
+export type SettingsPanelTag =
+  | "settings-general-panel"
+  | "settings-sessiond-panel"
+  | "settings-packages-panel"
+  | "settings-plugins-panel"
+  | "settings-shortcuts-panel";
+
+/**
+ * The single custom-element panel the settings dialog renders for a section.
+ *
+ * This is the public routing contract behind `renderActiveSection`: each section
+ * maps to exactly one panel element and nothing else (no per-tab "scope note"
+ * wrapper). Tests assert this mapping instead of inspecting the rendered
+ * `TemplateResult`'s markup.
+ */
+export function activeSettingsPanelTag(section: SettingsSection): SettingsPanelTag {
+  switch (section) {
+    case "sessiond":
+      return "settings-sessiond-panel";
+    case "packages":
+      return "settings-packages-panel";
+    case "plugins":
+      return "settings-plugins-panel";
+    case "shortcuts":
+      return "settings-shortcuts-panel";
+    case "general":
+      return "settings-general-panel";
+  }
+}