fix(api): close contract gaps found by post-merge adversarial audit

A 15-agent audit of the merged tree confirmed 9 envelope/contract bugs;
all fixed here, with live-server contract tests added:

Blockers (fresh-install quick start broken):
- session-ui.js runClaude/runShell unwrapped .data from the /api/cases/:name
  404 error envelope (which has no data key), so a not-yet-created case threw
  TypeError instead of triggering the auto-create fallback. Now '?.data ?? {}'.

Contract violations on the new stable surface:
- Unknown /api routes returned HTTP 404 with {success:true,...} (Fastify's
  default not-found payload was wrapped by the envelope hook). Added a
  setNotFoundHandler returning the standard error envelope for /api paths.
- POST /api/events/subscribe 400 body became {success:true,data:{error}};
  now createErrorResponse(INVALID_INPUT).
- POST /api/clipboard validation error lacked errorCode and shipped HTTP 200;
  now createErrorResponse(INVALID_INPUT) -> 400.
- POST /api/run catch path returned bare {success:false,sessionId,error}
  (HTTP 200, no errorCode); now OPERATION_FAILED envelope -> 422 with the
  dead session id in the message.
- DELETE tail-file/:streamId returned {success: closed}, colliding with the
  envelope discriminator; now returns {closed}.

Dead/regressed UI paths:
- Plan history modal could never open: route returned the bare history array
  under data while the frontend read data.data.history/currentVersion. Route
  now returns {history, currentVersion}; modal task count fixed to stats.total.
- Self-update error toast read j.error.message from the string-typed envelope
  error, always falling back to the generic message; now reads the string.

Cleanup:
- Removed the stale QuickStartResponse type (unreferenced; documented the
  pre-envelope shape and invited success-key collisions).

Tests: new test/http-contract.test.ts boots a real WebServer (port 3168) and
pins the envelope, /api/v1 alias, error statuses, and the /api 404 shape —
the route-test harness does not install the server-level hook, so these need
the live server. Updated file-routes/plan-routes/scheduled-runs tests to the
fixed shapes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/types/api.ts

@@ -113,22 +113,6 @@ export function createErrorResponse(code: ApiErrorCode, details?: string): ApiRe
   };
 }
 
-/**
- * Response for quick start operation
- */
-export interface QuickStartResponse {
-  /** Whether the request succeeded */
-  success: boolean;
-  /** Created session ID */
-  sessionId?: string;
-  /** Path to case folder */
-  casePath?: string;
-  /** Case name */
-  caseName?: string;
-  /** Error message if failed */
-  error?: string;
-}
-
 /**
  * Information about a case folder
  */

src/web/public/ralph-panel.js

@@ -1035,7 +1035,7 @@ Object.assign(CodemanApp.prototype, {
                    onclick="app.rollbackToPlanVersion(${item.version})">
                 <div>
                   <span class="plan-history-version">v${item.version}</span>
-                  <span class="plan-history-tasks">${item.taskCount || 0} tasks</span>
+                  <span class="plan-history-tasks">${item.stats?.total ?? 0} tasks</span>
                 </div>
                 <span class="plan-history-time">${this.formatRelativeTime(item.timestamp)}</span>
               </div>

src/web/public/session-ui.js

@@ -304,7 +304,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       // Get case path first
       const caseRes = await fetch(`/api/cases/${caseName}`);
-      let caseData = (await caseRes.json()).data;
+      let caseData = (await caseRes.json())?.data ?? {};
 
       // Create the case if it doesn't exist
       if (!caseData.path) {
@@ -452,7 +452,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       // Get the case path
       const caseRes = await fetch(`/api/cases/${caseName}`);
-      let caseData = (await caseRes.json()).data;
+      let caseData = (await caseRes.json())?.data ?? {};
 
       // Create the case if it doesn't exist
       if (!caseData.path) {

src/web/public/settings-ui.js

@@ -569,7 +569,7 @@ Object.assign(CodemanApp.prototype, {
     const res = await this._apiPost('/api/system/update', {});
     if (!res || !res.ok) {
       let msg = 'Failed to start the update.';
-      try { const j = await res.json(); if (j?.error?.message) msg = j.error.message; } catch {}
+      try { const j = await res.json(); if (typeof j?.error === 'string' && j.error) msg = j.error; } catch {}
       this._setUpdateProgress(`<span style="color:var(--danger,#e5534b)">${escapeHtml(msg)}</span>`);
       if (btn) { btn.disabled = false; btn.textContent = 'Update now'; }
       return;

src/web/routes/clipboard-routes.ts

@@ -6,13 +6,14 @@
 import { FastifyInstance } from 'fastify';
 import { SseEvent } from '../sse-events.js';
 import type { EventPort } from '../ports/index.js';
+import { createErrorResponse, ApiErrorCode } from '../../types.js';
 
 export function registerClipboardRoutes(app: FastifyInstance, ctx: EventPort): void {
   app.post('/api/clipboard', async (req) => {
     const body = req.body as { text?: string; sessionId?: string };
     const text = body?.text;
     if (typeof text !== 'string' || text.length === 0) {
-      return { success: false, error: 'Missing or empty "text" field' };
+      return createErrorResponse(ApiErrorCode.INVALID_INPUT, 'Missing or empty "text" field');
     }
     ctx.broadcast(SseEvent.ClipboardWrite, {
       text,

src/web/routes/file-routes.ts

@@ -375,12 +375,15 @@ export function registerFileRoutes(app: FastifyInstance, ctx: SessionPort): void
     });
   });
 
-  // Close a file stream
+  // Close a file stream. Returns { closed } rather than { success: closed } —
+  // a top-level `success` key would collide with the envelope discriminator
+  // (the preSerialization hook would pass `{success:false}` through as a
+  // malformed error envelope instead of wrapping it).
   app.delete('/api/sessions/:id/tail-file/:streamId', async (req) => {
     const { id, streamId } = req.params as { id: string; streamId: string };
     findSessionOrFail(ctx, id); // Validates session exists
     const closed = fileStreamManager.closeStream(streamId);
-    return { success: closed };
+    return { closed };
   });
   // Session-scoped file download.
   // Uses the same realpath-based workspace boundary as file preview/raw routes;

src/web/routes/plan-routes.ts

@@ -408,7 +408,7 @@ NOW: Generate the implementation plan for the task above. Think step by step.`;
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, 'Ralph tracker not available');
     }
 
-    return { success: true, data: tracker.getPlanHistory() };
+    return { success: true, data: { history: tracker.getPlanHistory(), currentVersion: tracker.planVersion } };
   });
 
   // ========== Rollback to Version ==========

src/web/routes/session-routes.ts

@@ -1086,9 +1086,10 @@ export function registerSessionRoutes(
       await ctx.cleanupSession(session.id, true, 'run_prompt_complete');
       return { sessionId: session.id, ...result };
     } catch (err) {
-      // Clean up session on error too
+      // Clean up session on error too. The session is destroyed here, so its id
+      // is only useful for log correlation — carry it in the error message.
       await ctx.cleanupSession(session.id, true, 'run_prompt_error');
-      return { success: false, sessionId: session.id, error: getErrorMessage(err) };
+      return createErrorResponse(ApiErrorCode.OPERATION_FAILED, `${getErrorMessage(err)} (session ${session.id})`);
     }
   });
 

src/web/server.ts

@@ -104,6 +104,7 @@ function rewriteApiV1Url(url: string): string {
 import {
   getErrorMessage,
   httpStatusForErrorCode,
+  createErrorResponse,
   ApiErrorCode,
   type PersistedRespawnConfig,
   type NiceConfig,
@@ -738,7 +739,7 @@ export class WebServer extends EventEmitter {
     this.app.post('/api/events/subscribe', (req, reply) => {
       const body = (req.body || {}) as { clientId?: string; sessions?: string[] | null };
       if (typeof body.clientId !== 'string' || !SSE_CLIENT_ID_RE.test(body.clientId)) {
-        reply.code(400).send({ error: 'clientId required' });
+        reply.code(400).send(createErrorResponse(ApiErrorCode.INVALID_INPUT, 'clientId required'));
         return;
       }
       const sessions = Array.isArray(body.sessions)
@@ -752,6 +753,18 @@ export class WebServer extends EventEmitter {
     // parseBody. Shared with the route test harness so test behavior matches prod.
     installRouteErrorHandler(this.app);
 
+    // Stable-contract 404 for unknown /api routes — without this, Fastify's
+    // default not-found payload {message,error,statusCode} would be wrapped by
+    // the envelope hook into a contradictory HTTP 404 {success:true,...}.
+    this.app.setNotFoundHandler((req, reply) => {
+      const notFound = `Route ${req.method}:${req.url} not found`;
+      if (req.url.startsWith('/api')) {
+        reply.code(404).send(createErrorResponse(ApiErrorCode.NOT_FOUND, notFound));
+        return;
+      }
+      reply.code(404).send({ message: notFound, error: 'Not Found', statusCode: 404 });
+    });
+
     // Crash diagnostics beacon — frontend POSTs breadcrumbs, GET to read them.
     // text/plain is used ONLY by this beacon (navigator.sendBeacon sends text/plain).
     // Keep the body as a RAW STRING and parse it inside the handler — a global