nomos+web: streaming, provider routing, event gap-fill, embedded UI; fix approval FK & session context

Agent (cmd/nomos):
- Stream LLM tokens via NewStreaming; emit text_delta then final text.
- OpenRouter provider routing: data_collection=deny (ZDR) + require_parameters;
  NOMOS_PROVIDER_SORT opt-in; Exacto via model suffix.
- Multi-turn: reload session history into context; UI passes session id.
- Fix agent_activity logging (agent_id/session_id) and mcpClient data race.

Events (live control-room feed):
- approval.created (mcp), approval.decided (api), execution.completed/failed
  (approved-action path), signal.raised/resolved + health.changed (scheduler,
  transition-gated).

Fixes:
- createApproval FK violation (reuse execution entity) — the agent's only
  write path; log the previously-swallowed errors.

Web UI:
- Embed web/dist via //go:embed (single binary); Dockerfile builds SPA into
  the Go stage; committed .gitkeep placeholder keeps backend-only builds green.
- Caddy: Authentik-gated /agent/* -> nomos so the UI reaches the agent
  same-origin in production.

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

web/src/lib/stores/chat.ts

@@ -0,0 +1,162 @@
+import { writable, get } from 'svelte/store'
+import { streamChat, fetchSessions, fetchMessages } from '$lib/api'
+import type { ChatEvent, Session, Message } from '$lib/api'
+
+export interface ChatMessage {
+  id: string
+  role: 'user' | 'assistant'
+  text: string
+  tools: ToolCallResult[]
+}
+
+export interface ToolCallResult {
+  type: 'tool_use' | 'tool_result'
+  name: string
+  id?: string
+  args?: any
+  result?: any
+  error?: string
+}
+
+function mid(): string {
+  return crypto.randomUUID()
+}
+
+export const messages = writable<ChatMessage[]>([])
+export const streaming = writable(false)
+export const currentSession = writable<string | null>(null)
+export const sessions = writable<Session[]>([])
+export const sessionMessages = writable<Message[]>([])
+export const error = writable<string | null>(null)
+
+let activeController: AbortController | null = null
+
+export async function loadSessions() {
+  const list = await fetchSessions()
+  sessions.set(list)
+}
+
+export async function loadSessionMessages(sessionId: string) {
+  currentSession.set(sessionId)
+  const msgs = await fetchMessages(sessionId)
+  sessionMessages.set(msgs)
+  const chatMsgs: ChatMessage[] = msgs.map((m) => ({
+    id: m.id,
+    role: m.role as 'user' | 'assistant',
+    text: m.content?.text ?? (typeof m.content === 'string' ? m.content : ''),
+    tools: m.content?.tool_calls ?? []
+  }))
+  messages.set(chatMsgs)
+}
+
+export function sendMessage(text: string) {
+  error.set(null)
+  streaming.set(true)
+
+  const userMsg: ChatMessage = {
+    id: mid(),
+    role: 'user',
+    text,
+    tools: []
+  }
+  messages.update((ms) => [...ms, userMsg])
+
+  const assistantMsg: ChatMessage = {
+    id: mid(),
+    role: 'assistant',
+    text: '',
+    tools: []
+  }
+  messages.update((ms) => [...ms, assistantMsg])
+
+  let activeTools: Map<string, ToolCallResult> = new Map()
+
+  activeController = streamChat(
+    text,
+    get(currentSession), // continue the active session so the agent keeps context
+    (ev: ChatEvent) => {
+      if (ev.type === 'session') {
+        currentSession.set(ev.data)
+      } else if (ev.type === 'tool_use') {
+        const tr: ToolCallResult = {
+          type: 'tool_use',
+          name: ev.data.name,
+          id: ev.data.id,
+          args: ev.data.args
+        }
+        activeTools.set(ev.data.id, tr)
+        messages.update((ms) => {
+          const last = ms[ms.length - 1]
+          if (last && last.role === 'assistant') {
+            last.tools = [...last.tools, tr]
+          }
+          return [...ms]
+        })
+      } else if (ev.type === 'tool_result') {
+        const existing = activeTools.get(ev.data.id)
+        if (existing) {
+          const updated: ToolCallResult = {
+            ...existing,
+            type: 'tool_result',
+            result: ev.data.result,
+            error: ev.data.error
+          }
+          activeTools.set(ev.data.id, updated)
+          messages.update((ms) => {
+            const last = ms[ms.length - 1]
+            if (last && last.role === 'assistant') {
+              last.tools = last.tools.map((t) =>
+                t.id === ev.data.id ? updated : t
+              )
+            }
+            return [...ms]
+          })
+        }
+      } else if (ev.type === 'text_delta') {
+        messages.update((ms) => {
+          const last = ms[ms.length - 1]
+          if (last && last.role === 'assistant') {
+            last.text += ev.data
+          }
+          return [...ms]
+        })
+      } else if (ev.type === 'text') {
+        // Final authoritative content for the turn; replaces accumulated deltas.
+        messages.update((ms) => {
+          const last = ms[ms.length - 1]
+          if (last && last.role === 'assistant') {
+            last.text = ev.data
+          }
+          return [...ms]
+        })
+      } else if (ev.type === 'done') {
+        currentSession.set(ev.data?.session_id ?? ev.session_id)
+      } else if (ev.type === 'error') {
+        error.set(ev.data)
+      }
+    },
+    (err: string) => {
+      error.set(err)
+    },
+    () => {
+      streaming.set(false)
+      activeController = null
+      loadSessions()
+    }
+  )
+}
+
+export function newChat() {
+  cancelStream()
+  currentSession.set(null)
+  messages.set([])
+  error.set(null)
+}
+
+export function cancelStream() {
+  if (activeController) {
+    activeController.abort()
+    activeController = null
+    streaming.set(false)
+  }
+}