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.

src/bootstrap/runtime-adapters.ts

@@ -505,6 +505,7 @@ export async function createRuntimeAdapters(
   });
   const featureInputs = createInstalledFeatureInputs({
     contractOperations,
+    studioSource: config.TECH_LOG_STUDIO_SOURCE,
   });
 
   return Object.freeze({

src/bootstrap/runtime-config-schema.ts

@@ -50,6 +50,12 @@ export type RuntimeConfig = Readonly<{
    * feature the build did not install cannot be named into existence here.
    */
   FEATURE_OVERRIDES: ProductFeatureOverrideMap;
+  /**
+   * §3.5-adjacent runtime switch: which Studio gateway adapter this build
+   * talks to. A V1 document predates the key and is always normalized to
+   * MOCK.
+   */
+  TECH_LOG_STUDIO_SOURCE: "MOCK" | "HTTP";
   /** Present only while a V1 document is still accepted. */
   LEGACY_API_CONTRACT_VERSION?: string;
 }>;
@@ -132,6 +138,11 @@ export function validateRuntimeConfig(value: unknown): RuntimeConfigValidation {
     FEATURE_OVERRIDES: Object.freeze({
       ...(isV2 ? (parsed as RuntimeConfigV2).FEATURE_OVERRIDES : {}),
     }),
+    // A V1 document predates the Studio adapter switch; it always normalizes
+    // to the mock so the backend-absent default holds for legacy documents.
+    TECH_LOG_STUDIO_SOURCE: isV2
+      ? (parsed as RuntimeConfigV2).TECH_LOG_STUDIO_SOURCE
+      : "MOCK",
     ...(isV2
       ? {}
       : {

src/contracts/env.ts

@@ -49,6 +49,9 @@ export const ENV_REGISTRY = Object.freeze({
   CAPABILITY_OVERRIDES: runtime("public", false, null),
   // §3.5: likewise for features — subtractive, keyed by installed feature id.
   FEATURE_OVERRIDES: runtime("public", false, null),
+  // TechLog Studio gateway adapter selection. Defaults to MOCK while the
+  // backend does not exist yet.
+  TECH_LOG_STUDIO_SOURCE: runtime("public", false, "MOCK"),
   // §3.5: build-time narrowing of the product manifest. A feature left out
   // here is not imported by any registry and never reaches the bundle.
   VITE_PRODUCT_FEATURES: build("compile-time", false, null),

src/contracts/release-artifacts.ts

@@ -156,6 +156,9 @@ export const runtimeConfigV2ArtifactSchema = z
     CONFIG_SCHEMA_VERSION: z.literal("2.0"),
     CAPABILITY_OVERRIDES: capabilityOverrideArtifactSchema,
     FEATURE_OVERRIDES: featureOverrideArtifactSchema,
+    // TechLog Studio adapter selection. Backend is not live yet, so the
+    // default is the in-memory mock; a document may opt a build into HTTP.
+    TECH_LOG_STUDIO_SOURCE: z.enum(["MOCK", "HTTP"]).default("MOCK"),
   })
   .strict()
   .superRefine(runtimeConfigArtifactInvariants);

src/features/installed-feature-adapters.ts

@@ -19,9 +19,10 @@ type InstalledFeatureInputs = Readonly<
 >;
 
 export function createInstalledFeatureInputs(
-  context: Parameters<typeof createReferenceFeatureInstalledInput>[0],
+  context: Parameters<typeof createReferenceFeatureInstalledInput>[0] &
+    Readonly<{ studioSource: "MOCK" | "HTTP" }>,
 ): InstalledFeatureInputs {
-  const techLogFeature = createTechLogFeatureInstalledInput();
+  const techLogFeature = createTechLogFeatureInstalledInput(context);
   if (!INSTALLED_PRODUCT_FEATURE_IDS.includes(REFERENCE_FEATURE_ID)) {
     // A build that narrowed the reference feature out still ships TechLog.
     return Object.freeze({

src/features/tech-log/adapters/create-tech-log-feature-input.ts

@@ -2,13 +2,36 @@ import {
   TECH_LOG_FEATURE_ID,
   type TechLogFeatureInput,
 } from "../application/tech-log-feature-input.ts";
+import {
+  createHttpStudioGateway,
+  type StudioOperationExecutor,
+} from "./http/http-studio-gateway.ts";
 import { createMockStudioGateway } from "./mock/mock-studio-gateway.ts";
 import { publicContentQueries } from "./static/public-query.ts";
 
-export function createTechLogFeatureInstalledInput() {
+/**
+ * The HTTP gateway builds no headers of its own — `Idempotency-Key` comes
+ * from the execution intent and credentials (including CSRF) come from the
+ * platform's `attachCredentials` collaborator at the composition root. This
+ * context only has to say which adapter to construct and hand it the
+ * composed contract executor.
+ */
+export type TechLogInstallContext = Readonly<{
+  studioSource: "MOCK" | "HTTP";
+  contractOperations: StudioOperationExecutor;
+}>;
+
+export function createTechLogFeatureInstalledInput(
+  context: TechLogInstallContext,
+) {
+  const createStudioGateway = () =>
+    context.studioSource === "MOCK"
+      ? createMockStudioGateway()
+      : createHttpStudioGateway({ operations: context.contractOperations });
+
   const input: TechLogFeatureInput = Object.freeze({
     publicContent: publicContentQueries,
-    createStudioGateway: () => createMockStudioGateway(),
+    createStudioGateway,
   });
 
   return Object.freeze({