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/component/product-feature-switch.test.tsx

@@ -5,6 +5,7 @@ import { describe, expect, it, vi } from "vitest";
 
 import { createAnonymousSessionAdapter } from "../../src/adapters/auth/external-session-adapter.ts";
 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 { createTestApplication } from "../helpers/create-test-application.ts";
 import { createProductFeaturesStub } from "../helpers/runtime-capabilities-stub.ts";
 
@@ -55,7 +56,7 @@ function renderAt(path: string, disabled: boolean) {
     <ApplicationProvider
       application={createTestApplication({
         session: createAnonymousSessionAdapter(),
-        featureInputs: { "tech-log": createTechLogFeatureInstalledInput().input },
+        featureInputs: { "tech-log": createTechLogFeatureInstalledInput(MOCK_STUDIO_INSTALL_CONTEXT).input },
         ...(disabled
           ? {
               productFeatures: createProductFeaturesStub({