Merge updated DeepSeek onboarding base

# Conflicts:
#	packages/host/apiproxy/README.i18n.yaml

packages/host/apiproxy/src/api-proxy.ts

@@ -1276,6 +1276,75 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         }
       },
 
+      async fork(request) {
+        const { sessionId, atSeq } = request.payload
+        const found = await agentFor(sessionId)
+        if ('error' in found) return err(request, found.error)
+        const source = found.agent.session
+        const events = source.events
+        // An in-log anchor belongs to the turn containing it and must never
+        // clip backward to an earlier completed turn. Omitted and past-end
+        // anchors retain the last-completed-turn shortcut.
+        const lastSeq = events.at(-1)?.seq ?? -1
+        const anchoredBoundary = atSeq === undefined
+          ? undefined
+          : events.find(e => e.type === 'turn/end' && e.seq >= atSeq)
+        const boundary = anchoredBoundary
+          ?? (atSeq === undefined || atSeq > lastSeq
+            ? events.findLast(e => e.type === 'turn/end')
+            : undefined)
+        if (boundary === undefined) {
+          return err(request, {
+            code: 'fork-unavailable',
+            message: atSeq !== undefined && atSeq <= lastSeq
+              ? `session "${sessionId}" has not completed the turn containing event ${String(atSeq)}`
+              : `session "${sessionId}" has no completed turn to fork from`,
+            details: { sessionId },
+          })
+        }
+        // Extend the cut through trailing out-of-band appends (session/title,
+        // injections) up to the next turn/start: they are standalone events, so
+        // the seed stays balanced, and the child inherits a title generated
+        // right after the boundary turn.
+        let cut = boundary.seq + 1
+        while (cut < events.length && events[cut]?.type !== 'turn/start') cut++
+        const childId = `session-${randomUUID()}` as SessionId
+        try {
+          await ctx.agents.create({
+            sessionId: childId,
+            seed: events.slice(0, cut),
+            meta: {
+              ...source.header.cwd === undefined ? {} : { cwd: source.header.cwd },
+              parentSession: source.id,
+              seedLength: cut,
+            },
+            agentOptions,
+            setup: installTarget,
+          })
+        } catch (error: unknown) {
+          return err(request, {
+            code: 'internal',
+            message: `failed to fork session "${sessionId}": ${String(error)}`,
+            details: {},
+          })
+        }
+        // Keep the child in the source's Workspace so the list nests it under
+        // its parent; the child is already published if the attach fails.
+        const workspace = ctx.workspace.list().find(w => w.sessionIds.includes(source.id))
+        if (workspace !== undefined) {
+          try {
+            await workspace.attachSession(childId)
+          } catch (error: unknown) {
+            return err(request, {
+              code: 'workspace-attach-failed',
+              message: `session "${childId}" was forked but could not attach to workspace "${workspace.id}": ${String(error)}`,
+              details: { sessionId: childId, workspaceId: workspace.id },
+            })
+          }
+        }
+        return ok(request, { sessionId: childId })
+      },
+
       async prompt(request) {
         const { sessionId, mode, content } = request.payload
         const found = await agentFor(sessionId)

packages/host/apiproxy/src/api/events.schema.ts

@@ -23,6 +23,11 @@ export const askUserQuestionItemSchema = z.object({
   detail: z.string().optional(),
   options: z.array(z.object({ label: z.string(), description: z.string().optional() })).optional(),
   multiSelect: z.boolean().optional(),
+  // Presentation intent: a tagged union on the wire, so an unknown tag is a
+  // rejected frame rather than a silently generic render.
+  intent: z.discriminatedUnion('kind', [
+    z.object({ kind: z.literal('plan-review'), approve: z.string() }),
+  ]).optional(),
 }) satisfies z.ZodType<Wire<AskUserQuestionItem>>
 
 /** Unified message envelope carried by transient queue frames. */

packages/host/apiproxy/src/api/rpc-map.ts

@@ -27,6 +27,7 @@ export interface RpcMethodMap {
   'session.models': SessionsApi['models']
   'session.selectModel': SessionsApi['selectModel']
   'session.rename': SessionsApi['rename']
+  'session.fork': SessionsApi['fork']
   'session.prompt': SessionsApi['prompt']
   'session.updateQueue': SessionsApi['updateQueue']
   'session.cancel': SessionsApi['cancel']

packages/host/apiproxy/src/api/rpc.schema.ts

@@ -55,6 +55,7 @@ export const rpcErrorSchema: z.ZodType<RpcError> = z.discriminatedUnion('code',
   z.object({ code: z.literal('settings-conflict'), message: z.string(), details: z.object({ ns: z.string(), expected: z.number(), actual: z.number() }) }),
   z.object({ code: z.literal('credential-rejected'), message: z.string(), details: z.object({ ref: z.string() }) }),
   z.object({ code: z.literal('title-invalid'), message: z.string(), details: z.object({ sessionId: z.string() }) }),
+  z.object({ code: z.literal('fork-unavailable'), message: z.string(), details: z.object({ sessionId: z.string() }) }),
   z.object({ code: z.literal('internal'), message: z.string(), details: z.object({}) }),
 ]) as unknown as z.ZodType<RpcError>
 

packages/host/apiproxy/src/api/rpc.ts

@@ -70,6 +70,7 @@ export interface RpcErrorDetailsMap {
   /** A credential write was refused (read-only shadowing layer or storage failure); the message is the seam's own text. */
   'credential-rejected': { ref: string }
   'title-invalid': { sessionId: SessionId }
+  'fork-unavailable': { sessionId: SessionId }
   'internal': {}
 }
 

packages/host/apiproxy/src/api/sessions.schema.ts

@@ -89,6 +89,17 @@ export const sessionRenameValueSchema = z.object({
   seq: z.number().int().nonnegative(),
 }) satisfies z.ZodType<Wire<ResponseValue<'session.rename'>>>
 
+/** session.fork request payload (atSeq anchors the completed-turn cut). */
+export const sessionForkRequestSchema = z.object({
+  sessionId: sessionIdSchema,
+  atSeq: z.number().int().nonnegative().optional(),
+}) satisfies z.ZodType<Wire<RequestPayload<'session.fork'>>>
+
+/** session.fork response value (the child session id). */
+export const sessionForkValueSchema = z.object({
+  sessionId: sessionIdSchema,
+}) satisfies z.ZodType<Wire<ResponseValue<'session.fork'>>>
+
 /** session.history request payload (beforeSeq/maxMessages page backwards from the window tail). */
 export const sessionHistoryRequestSchema = z.object({
   sessionId: sessionIdSchema,

packages/host/apiproxy/src/api/sessions.ts

@@ -238,6 +238,21 @@ export interface SessionsApi {
    * one — carried for future rendering; the state change is the feedback). A usage/state error is an
    * RPC error with code command-error; an unrecognized name is an RPC error with code unknown-command.
    */
+  /**
+   * Forks a new session from a completed-turn prefix of the source. `atSeq`
+   * anchors the cut: the boundary is the first `turn/end` at or after it
+   * (a message's fork button passes the message seq, so the fork includes
+   * that whole turn); a boundary past the log end, or an omitted `atSeq`,
+   * falls back to the source's last completed turn. An in-log anchor whose
+   * turn is still open fails with `fork-unavailable` instead of clipping to
+   * an earlier turn. The child inherits the source cwd, latest logged model
+   * target, workspace attachment, and `parentSessionId` lineage; the seed
+   * prefix carries the source title.
+   */
+  fork(request: RpcRequest<{ sessionId: SessionId; atSeq?: number }>):
+  Promise<RpcResponse<{ sessionId: SessionId }>>
+
+  /** Sends a message. content is core's ContentBlock[] verbatim; mode maps 1:1 — queue→send, steer→steer. */
   prompt(request: RpcRequest<{ sessionId: SessionId; mode: 'queue' | 'steer'; content: ContentBlock[] }>):
   Promise<RpcResponse<{ accepted: true; command?: { kind: 'success'; text?: string } }>>
 

packages/host/apiproxy/src/fetch/client.ts

@@ -20,6 +20,7 @@ import {
 import {
   sessionCancelValueSchema,
   sessionCreateValueSchema,
+  sessionForkValueSchema,
   sessionHistoryValueSchema,
   sessionListValueSchema,
   sessionModelsValueSchema,
@@ -76,6 +77,7 @@ export interface IApiClient {
     models(payload: RequestPayload<'session.models'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.models'>>>
     selectModel(payload: RequestPayload<'session.selectModel'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.selectModel'>>>
     rename(payload: RequestPayload<'session.rename'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.rename'>>>
+    fork(payload: RequestPayload<'session.fork'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.fork'>>>
     prompt(payload: RequestPayload<'session.prompt'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.prompt'>>>
     updateQueue(payload: RequestPayload<'session.updateQueue'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.updateQueue'>>>
     cancel(payload: RequestPayload<'session.cancel'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.cancel'>>>
@@ -143,6 +145,7 @@ const UNARY_VALUE_SCHEMAS: { [K in keyof RpcMethodMap]: z.ZodType<Wire<ResponseV
   'session.models': sessionModelsValueSchema,
   'session.selectModel': sessionSelectModelValueSchema,
   'session.rename': sessionRenameValueSchema,
+  'session.fork': sessionForkValueSchema,
   'session.prompt': sessionPromptValueSchema,
   'session.updateQueue': sessionUpdateQueueValueSchema,
   'session.cancel': sessionCancelValueSchema,
@@ -365,6 +368,7 @@ export abstract class AbstractApiClient implements IApiClient {
     models: (payload, signal) => this.callUnary('session.models', payload, signal),
     selectModel: (payload, signal) => this.callUnary('session.selectModel', payload, signal),
     rename: (payload, signal) => this.callUnary('session.rename', payload, signal),
+    fork: (payload, signal) => this.callUnary('session.fork', payload, signal),
     prompt: (payload, signal) => this.callUnary('session.prompt', payload, signal),
     updateQueue: (payload, signal) => this.callUnary('session.updateQueue', payload, signal),
     cancel: (payload, signal) => this.callUnary('session.cancel', payload, signal),

packages/host/apiproxy/src/fetch/handler.ts

@@ -17,6 +17,7 @@ import { clientRequestSchema, clientResponseSchema } from '../api/rpc.schema.ts'
 import {
   sessionCancelRequestSchema,
   sessionCreateRequestSchema,
+  sessionForkRequestSchema,
   sessionHistoryRequestSchema,
   sessionListRequestSchema,
   sessionModelsRequestSchema,
@@ -78,6 +79,7 @@ const UNARY_ROUTES: UnaryRoutes = {
   'session.models': { schema: sessionModelsRequestSchema, invoke: (api, r) => api.sessions.models(r) },
   'session.selectModel': { schema: sessionSelectModelRequestSchema, invoke: (api, r) => api.sessions.selectModel(r) },
   'session.rename': { schema: sessionRenameRequestSchema, invoke: (api, r) => api.sessions.rename(r) },
+  'session.fork': { schema: sessionForkRequestSchema, invoke: (api, r) => api.sessions.fork(r) },
   'session.prompt': { schema: sessionPromptRequestSchema, invoke: (api, r) => api.sessions.prompt(r) },
   'session.updateQueue': { schema: sessionUpdateQueueRequestSchema, invoke: (api, r) => api.sessions.updateQueue(r) },
   'session.cancel': { schema: sessionCancelRequestSchema, invoke: (api, r) => api.sessions.cancel(r) },