feat: select the TechLog Studio adapter from runtime configuration

Adds TECH_LOG_STUDIO_SOURCE (MOCK | HTTP, default MOCK) to the V2 runtime
config schema so a build can switch createTechLogFeatureInstalledInput
between the mock and HTTP Studio gateways without a rebuild. V1 documents
predate the key and always normalize to MOCK. The HTTP gateway is
constructed with only { operations } per Task 4's actual signature -
no CSRF provider is wired here; that lands with attachCredentials at a
later composition-root task.

Updates every existing Studio test call site to the new required
createTechLogFeatureInstalledInput(context) signature via a shared
tests/helpers/studio-install-context.ts MOCK fixture, so the whole
existing Studio suite keeps exercising the mock adapter unchanged.

tests/features/tech-log/public-discovery-screens.test.tsx

@@ -12,6 +12,7 @@ import {
 } from "react-router-dom";
 
 import { createTechLogFeatureInstalledInput } from "../../../src/features/tech-log/adapters/create-tech-log-feature-input.ts";
+import { MOCK_STUDIO_INSTALL_CONTEXT } from "../../helpers/studio-install-context.ts";
 import {
   TECH_LOG_ROUTE_REGISTRY,
   TECH_LOG_ROUTE_RUNTIME_CONTRACT,
@@ -90,7 +91,7 @@ function renderDiscoveryRoute<RouteId extends DiscoveryRouteId>(
     ),
     { initialEntries: [initialEntry] },
   );
-  const techLog = createTechLogFeatureInstalledInput().input;
+  const techLog = createTechLogFeatureInstalledInput(MOCK_STUDIO_INSTALL_CONTEXT).input;
   const view = render(
     <ApplicationProvider
       application={
@@ -415,7 +416,7 @@ describe("TechLog explore discovery", () => {
       routeChunks,
     };
     const record = vi.fn();
-    const techLog = createTechLogFeatureInstalledInput().input;
+    const techLog = createTechLogFeatureInstalledInput(MOCK_STUDIO_INSTALL_CONTEXT).input;
     const application = createTestApplication({
       diagnostics: { record },
       releaseInfo: {