feat(chat): single-call console for general.help, persisted, runs on a local model (#1762)

RIP-3 cutover. The free-form /chat panel (general.help) now answers through a
page-scoped single-call console (AskConsole → POST /api/agent/ask) instead of
the streaming Anthropic runtime, so the in-app assistant runs on ANY configured
backend, including a local OpenAI-compatible model (Qwen behind
llama.cpp/Ollama/vLLM). No tool loop, no NDJSON stream, no Anthropic wire format.

Threads still persist: the ask route gains an opt-in persist branch that writes
both turns to agent_conversations/agent_messages as canonical Anthropic text
blocks, so the /chat sidebar and "resume a thread" keep working across old
streaming threads and new single-call ones. Page-scoped one-off asks (a report
page) omit persist and stay stateless.

Scope: only general.help is wired to the console. The tool-loop intents
(transaction.categorization, invoice.draft, supplier_invoice.review) and the
docked AgentSheet still use AgentChat + run-turn.ts because they stage
operations and need the tool loop, so run-turn.ts is intentionally NOT deleted
here (the plan gates its deletion on "once nothing calls them"; RIP-4 migrates
the rest).

- lib/agent/ask/persist.ts: resolveChatConversation (create/resume, ownership),
  persistUserTurn, persistAssistantTurn (append + roll last_message_* forward)
- app/api/agent/ask/route.ts: persist branch (resolve → user turn → answer →
  assistant turn), returns conversation_id; 404 on a foreign conversation
- components/agent/AskConsole.tsx: the console UI (approved sign-off design):
  user bubble + bare-prose answer, thinking indicator, empty/503/paywall states
- ChatConversationView / ChatNewStarter: branch general.help → AskConsole,
  every other intent keeps AgentChat unchanged

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

components/agent/ChatConversationView.tsx

@@ -4,6 +4,8 @@ import { useMemo } from 'react'
 import Link from 'next/link'
 import { ArrowLeft } from 'lucide-react'
 import AgentChat, { attachStagedOperations, normalizeStoredMessages } from './AgentChat'
+import AskConsole, { type AskConsoleMessage } from './AskConsole'
+import { CHAT_INTENT_ID } from '@/lib/agent/ask/persist'
 import type { StoredStagedOperation } from '@/types'
 import AgentAvatar from './AgentAvatar'
 import ContextChip from './ContextChip'
@@ -37,6 +39,17 @@ export default function ChatConversationView({
     () => attachStagedOperations(normalizeStoredMessages(rawMessages), stagedOperations ?? []),
     [rawMessages, stagedOperations],
   )
+  // general.help runs on the single-call console; it never stages operations,
+  // so the thread is text-only. Empty turns (a historical pure-tool_use row
+  // from the old runtime) are dropped rather than rendered as blank rows.
+  const isSingleCall = intentId === CHAT_INTENT_ID
+  const consoleMessages = useMemo<AskConsoleMessage[]>(
+    () =>
+      normalizeStoredMessages(rawMessages)
+        .filter((m) => m.text.trim().length > 0)
+        .map((m) => ({ role: m.role, text: m.text })),
+    [rawMessages],
+  )
   const { identity } = useAgentSheet()
   const companyCtx = useCompanyOptional()
   const isSandbox = companyCtx?.isSandbox ?? false
@@ -71,6 +84,13 @@ export default function ChatConversationView({
       <div className="flex-1 min-h-0 flex flex-col">
         {isSandbox ? (
           <SandboxAgentPreview agentName={agentName} />
+        ) : isSingleCall ? (
+          <AskConsole
+            initialConversationId={conversationId}
+            initialMessages={consoleMessages}
+            contextRef={contextRef}
+            scrollerClassName="px-6 py-8"
+          />
         ) : (
           <AgentChat
             intentId={intentId}