feat(web): re-land the goals wire domain as mutation-only ref acknowledgements

Six mutation RPCs (create/edit/pause/resume/complete/clear) move into
dsh-host-apiproxy (the PR's host/runtime carrier is gone): goalService()
resolves ctx.get('goals') with a loud absence error, mutateGoal() resolves
the session's agent (agentFor, the command.* implicit-resume precedent) and
acknowledges with the new CAS ref only. GoalError codes ride err.details.

goal.get and the wire GoalView/goalViewSchema are gone: the read side is the
'goal' session projection (whole values on the history tail page and
session/projection frames), so responses never feed client state — the rule
whose absence forced the original PR's write-revision fences.

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

@@ -24,12 +24,15 @@ import {
 // Type-only: brings the `ctx.tools` Context merge into this program (viewFor reads presenters).
 import type {} from '@deepseek-ai/dsh-tools'
 import type {
-  ApiProxy, HistoryEntry, HostFrame, ModelCatalogFailure, ModelProviderGroup, ModelReasoning,
+  ApiProxy, GoalRef, HistoryEntry, HostFrame, ModelCatalogFailure, ModelProviderGroup, ModelReasoning,
   MuxFrame, QuestionResponsePayload, SessionProjectionsBlock, SessionSummary, ToolEventView,
   WorkspaceId, WorkspaceView,
 } from './api/index.ts'
 // Type-only: resolves `ctx.get('sessionProjections')` to the projection registry.
 import type {} from '@deepseek-ai/dsh-session-projection'
+// GoalError narrows domain rejections to their stable codes at the wire boundary.
+import { GoalError } from '@deepseek-ai/dsh-goal'
+import type { GoalRef as CoreGoalRef } from '@deepseek-ai/dsh-goal'
 // Type-only edges: resolve `ctx.get('commands')`, the `commands/change` event, and `ctx.get('skills')`.
 import type {} from '@deepseek-ai/dsh-commands'
 import type {} from '@deepseek-ai/dsh-skill'
@@ -645,6 +648,38 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
     return operation
   }
 
+  /** Resolve the goal service; absent = the deployment did not compose @deepseek-ai/dsh-goal. */
+  function goalService(): NonNullable<ReturnType<typeof ctx.get<'goals'>>> | { error: RpcError } {
+    const goals = ctx.get('goals')
+    if (goals === undefined) {
+      return { error: { code: 'internal', message: 'goal service is absent: this deployment does not mount @deepseek-ai/dsh-goal in its composition (cordis.yml or explicit assembly)', details: {} } }
+    }
+    return goals
+  }
+
+  /** Map one goal-domain rejection to the wire error (stable GoalError codes ride in details). */
+  function goalError(request: RpcRequest<unknown>, error: unknown): RpcResponse<never> {
+    const details = error instanceof GoalError ? { goalCode: error.code } : {}
+    return err(request, { code: 'internal', message: String(error), details })
+  }
+
+  /** Resolve a session's agent, apply one goal mutation, and acknowledge with the new CAS ref. */
+  async function mutateGoal(
+    request: RpcRequest<{ sessionId: SessionId }>,
+    mutation: (goals: NonNullable<ReturnType<typeof ctx.get<'goals'>>>, agent: Agent) => CoreGoalRef,
+  ): Promise<RpcResponse<{ ref: GoalRef }>> {
+    const goals = goalService()
+    if ('error' in goals) return err(request, goals.error)
+    const found = await agentFor(request.payload.sessionId)
+    if ('error' in found) return err(request, found.error)
+    try {
+      const ref = mutation(goals, found.agent)
+      return ok(request, { ref: { id: ref.id, revision: ref.revision } })
+    } catch (error: unknown) {
+      return goalError(request, error)
+    }
+  }
+
   return {
     sessions: {
       // Attached sessions summarize from memory; persisted-but-unattached (cold)
@@ -1090,6 +1125,54 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
       },
     },
 
+    goals: {
+      // Mutations only — the read side is the 'goal' session projection.
+      // Every verb resolves the session's agent (agentFor: implicit cold
+      // resume, the command.* precedent) and acknowledges with the new CAS
+      // ref; the committed goal/change event carries the whole value to every
+      // client through the projection frames.
+      async create(request) {
+        const { objective, maxGoalRounds } = request.payload
+        return mutateGoal(request, (goals, agent) => goals.create(agent, {
+          objective,
+          ...(maxGoalRounds !== undefined ? { maxGoalRounds } : {}),
+        }))
+      },
+
+      async edit(request) {
+        const { ref, objective, maxGoalRounds } = request.payload
+        return mutateGoal(request, (goals, agent) => goals.edit(agent, ref, {
+          ...(objective !== undefined ? { objective } : {}),
+          ...(maxGoalRounds !== undefined ? { maxGoalRounds } : {}),
+        }))
+      },
+
+      async pause(request) {
+        return mutateGoal(request, (goals, agent) => goals.pause(agent, request.payload.ref))
+      },
+
+      async resume(request) {
+        return mutateGoal(request, (goals, agent) => goals.resume(agent, request.payload.ref))
+      },
+
+      async complete(request) {
+        return mutateGoal(request, (goals, agent) => goals.complete(agent, request.payload.ref))
+      },
+
+      async clear(request) {
+        const goals = goalService()
+        if ('error' in goals) return err(request, goals.error)
+        const found = await agentFor(request.payload.sessionId)
+        if ('error' in found) return err(request, found.error)
+        try {
+          goals.clear(found.agent, request.payload.ref)
+          return ok(request, { cleared: true as const })
+        } catch (error: unknown) {
+          return goalError(request, error)
+        }
+      },
+    },
+
     skills: {
       // Skill lookup never touches the Agent registry: the session address
       // resolves to a canonical cwd from the host-resident session header, so