refactor(studio): reorganize source tree by domain layer

harness-studio's src/ had accumulated a flat, inconsistent layout: a
2723-line server.ts route dispatcher, artifact-format files mixed
with plugin registry files, a session-debugger-model.ts that mixed
shared types with server-only logic and a server -> app reverse
dependency, and artifact views split across app/ and app/artifacts/.

- Extract src/contracts/ for types shared by app and server, dropping
  the redundant "-model" suffix and merging the duplicate 2-line
  artifact re-export.
- Split session-debugger-model.ts into contracts/debugger-session.ts
  (types), server/debugger-session-transform.ts (retained-run
  conversion), and app/run/{debugger-cursor,sample-debugger-session}.ts
  (UI navigation and the recorded-sample fixture), removing the
  server -> app dependency.
- Consolidate ArtifactView/ArtifactPreviewHost/MarkdownArtifactView
  into app/artifacts/ alongside the other Artifact Surface views.
- Group server/ into artifacts/{registry,adapters}/,
  providers/{qoder,walnut}/, experiment/, and workspace/; extract
  StudioIntentAnalyzer out of server.ts so the Qoder provider no
  longer depends on the route-dispatcher file for one interface.
- Split server.ts's route handlers into per-domain modules
  (studio-types, http-utils, acp-runs, workspace/routes, git/routes,
  artifacts/routes, experiment/routes, content-routes), leaving
  server.ts as a thin dispatcher plus the server factory.
- Group app/ into run/, experiment/, and code/ for each multi-file
  feature area; single-view areas stay flat.
- Split src/index.ts into a browser-safe src/client.ts (also
  published as the "./client" export) and the Node-only server/CLI
  surface.

Verified after every step with tsc --noEmit (diffed against a
captured baseline of pre-existing, unrelated errors from a stale
sibling package build) and vitest run (265/266 passing throughout,
matching the pre-existing baseline exactly).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: phodal

packages/harness-studio/README.md

@@ -106,20 +106,41 @@ fingerprint never enters selection.
 ## Architecture
 
 ```text
-dist/app/        esbuild-bundled React app (index.html + assets/app.js)
-src/app/         components plus pure state modules:
-                   agui-store.ts     AG-UI event → run view state reducer
-                   compare-model.ts  verdict.json → table model
-                   sse-client.ts     incremental SSE frame parser
-                   studio-shell-model.ts
-                                        config → IA/readiness projection
-src/server/      static host + /api/config + /api/evidence + embedded /agui
-                 read-only /inspector + checkpoint history list/resolve
-                 + durable experiment lock
+dist/app/          esbuild-bundled React app (index.html + assets/app.js)
+src/contracts/      types and wire formats shared by app and server
+                     (artifact, debugger-session, experiment, git-history,
+                     input-trace, intent-correlation, workspace-artifact)
+src/app/            shell (App.tsx, studio-shell-model.ts, studio-theme.ts)
+                     plus feature areas, each a components+state pair:
+                       run/          live run view, AG-UI reducer, Debugger
+                                     cursor navigation, recorded sample
+                       experiment/   three-lane experiment trace view
+                       artifacts/    per-format Artifact Surface views and
+                                     the surface registry
+                       code/         shared code/diff rendering (Shiki
+                                     highlighting, ArtifactCodeView)
+                     and single-view areas at the top level (Compare,
+                     Customizations, GitHistory, InputTrace, Inspector,
+                     ArtifactsWorkspace)
+src/server/          static host + /api/config + /api/evidence + embedded
+                     /agui, grouped by domain:
+                       artifacts/registry/   catalog, compile runtime,
+                                             Provider activation/discovery
+                       artifacts/adapters/   built-in docx/markdown/pdf/
+                                             pptx/xlsx format adapters
+                       providers/qoder/      Qoder-specific Provider,
+                                             Canvas bridge, intent analyzer
+                       providers/walnut/     Walnut Provider and bootstrap
+                       experiment/           experiment events + locking
+                       workspace/            workspace/session discovery
+                       query/               read-only route query helpers
 ```
 
 The pure modules are the tested seam; the React components are direct renders
-of their outputs.
+of their outputs. `src/index.ts` is the Node entry point (server, CLI,
+Provider activation); `src/client.ts` re-exports only the browser-safe subset
+(also available from the package as `@qoder-ai/harness-studio/client`) so a
+browser bundle never pulls in Node-only code.
 
 ## Development
 

packages/harness-studio/package.json

@@ -22,6 +22,10 @@
     ".": {
       "types": "./dist/index.d.ts",
       "import": "./dist/index.js"
+    },
+    "./client": {
+      "types": "./dist/client.d.ts",
+      "import": "./dist/client.js"
     }
   },
   "files": [

packages/harness-studio/scripts/start-inspector-workspace.mjs

@@ -8,7 +8,7 @@ import { createInspectorWorkspaceSessionProvider } from "./inspector-workspace-p
 const packageRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
 const repositoryRoot = path.resolve(packageRoot, "../..");
 const { startHarnessStudioServer } = await import(path.join(packageRoot, "dist", "server", "server.js"));
-const { createQoderCliIntentAnalyzer } = await import(path.join(packageRoot, "dist", "server", "qoder-intent-analyzer.js"));
+const { createQoderCliIntentAnalyzer } = await import(path.join(packageRoot, "dist", "server", "providers", "qoder", "intent-analyzer.js"));
 const { createBundledAgentCustomizationCollector } = await import(path.join(packageRoot, "dist", "server", "customization-collector.js"));
 const portIndex = process.argv.indexOf("--port");
 const requestedPort = portIndex >= 0 ? Number(process.argv[portIndex + 1]) : 3311;

packages/harness-studio/src/app/App.tsx

@@ -16,11 +16,11 @@ import { Sun } from "@phosphor-icons/react/Sun";
 import { ArtifactsWorkspace } from "./ArtifactsWorkspace.js";
 import { CompareView } from "./CompareView.js";
 import { CustomizationView } from "./CustomizationView.js";
-import { ExperimentView } from "./ExperimentView.js";
+import { ExperimentView } from "./experiment/ExperimentView.js";
 import { GitHistoryView } from "./GitHistoryView.js";
 import { InputTraceView } from "./InputTraceView.js";
-import { RunView } from "./RunView.js";
-import type { DebuggerSession } from "./session-debugger-model.js";
+import { RunView } from "./run/RunView.js";
+import type { DebuggerSession } from "../contracts/debugger-session.js";
 import { useRovingFocus } from "./roving-tablist.js";
 import { studioApiError } from "./studio-api.js";
 import { StudioThemeContext, type StudioTheme } from "./studio-theme.js";

packages/harness-studio/src/app/ArtifactsWorkspace.tsx

@@ -16,14 +16,14 @@ import { TreeStructure } from "@phosphor-icons/react/TreeStructure";
 import {
   isArtifactCatalogResponse,
   type ArtifactDescriptor,
-} from "../artifact-model.js";
+} from "../contracts/artifact.js";
 import {
   isWorkspaceArtifactNavigation,
   type StudioArtifactCatalogResponse,
   type WorkspaceArtifactNavigation,
   type WorkspaceArtifactObservation,
-} from "../workspace-artifact-model.js";
-import { ArtifactView } from "./ArtifactView.js";
+} from "../contracts/workspace-artifact.js";
+import { ArtifactView } from "./artifacts/ArtifactView.js";
 import { useRovingFocus } from "./roving-tablist.js";
 import type { StudioConfig } from "./studio-shell-model.js";
 

packages/harness-studio/src/app/GitHistoryView.tsx

@@ -27,8 +27,8 @@ import {
   type GitHistoryRef,
   type GitLogPage,
   type GitRefsSnapshot,
-} from "../git-history-model.js";
-import { ArtifactCodeView } from "./ArtifactCodeView.js";
+} from "../contracts/git-history.js";
+import { ArtifactCodeView } from "./code/ArtifactCodeView.js";
 
 const PAGE_SIZE = 40;
 const GIT_LANE_COLOR_TOKENS = [5, 4, 2, 1, 6, 7, 3] as const;

packages/harness-studio/src/app/InputTraceView.tsx

@@ -12,12 +12,12 @@ import {
   type UserInputFileTreeNode,
   type UserInputRecord,
   type UserInputTraceV1,
-} from "../input-trace-model.js";
+} from "../contracts/input-trace.js";
 import {
   isIntentCorrelationAnalysis,
   type IntentCorrelationAnalysisV1,
   type IntentProposal,
-} from "../intent-correlation-model.js";
+} from "../contracts/intent-correlation.js";
 
 type ActivityFilter = "all" | UserInputActivity | "unlinked";
 

packages/harness-studio/src/app/artifacts/ArtifactDiagnostics.tsx

@@ -1,4 +1,4 @@
-import type { ArtifactDataSnapshot } from "../../artifact-model.js";
+import type { ArtifactDataSnapshot } from "../../contracts/artifact.js";
 
 export function ArtifactDiagnostics({ diagnostics }: {
   diagnostics: ArtifactDataSnapshot["diagnostics"];

…s-studio/src/app/ArtifactPreviewHost.tsx …rc/app/artifacts/ArtifactPreviewHost.tsxpackages/harness-studio/src/app/ArtifactPreviewHost.tsx renamed to packages/harness-studio/src/app/artifacts/ArtifactPreviewHost.tsx packages/harness-studio/src/app/ArtifactPreviewHost.tsx renamed to packages/harness-studio/src/app/artifacts/ArtifactPreviewHost.tsx

@@ -3,11 +3,11 @@ import {
   isArtifactBuildSnapshot,
   type ArtifactBuildSnapshot,
   type ArtifactDescriptor,
-} from "../artifact-model.js";
-import { ArtifactCodeView } from "./ArtifactCodeView.js";
-import { useRovingTablist } from "./roving-tablist.js";
-import { studioApiError } from "./studio-api.js";
-import { useStudioTheme } from "./studio-theme.js";
+} from "../../contracts/artifact.js";
+import { ArtifactCodeView } from "../code/ArtifactCodeView.js";
+import { useRovingTablist } from "../roving-tablist.js";
+import { studioApiError } from "../studio-api.js";
+import { useStudioTheme } from "../studio-theme.js";
 
 type PreviewState = "compiling" | "starting" | "ready" | "compile-failed" | "runtime-failed";
 type PreviewSurface = "preview" | "source";

packages/harness-studio/src/app/artifacts/ArtifactSurface.ts

@@ -1,5 +1,5 @@
 import type { ComponentType } from "react";
-import type { ArtifactDescriptor } from "../../artifact-model.js";
+import type { ArtifactDescriptor } from "../../contracts/artifact.js";
 
 export interface ArtifactSurfaceMountContext {
   artifact: ArtifactDescriptor;