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/App.svelte

@@ -0,0 +1,155 @@
+<script lang="ts">
+  import Chat from '$lib/../pages/Chat.svelte'
+  import Sessions from '$lib/../pages/Sessions.svelte'
+  import { newChat } from '$lib/stores/chat'
+  import { onMount } from 'svelte'
+  import { slide } from 'svelte/transition'
+
+  let page = $state('chat')
+  let drawerOpen = $state(false)
+
+  onMount(() => {
+    function sync() {
+      page = location.hash.slice(2) || 'chat'
+    }
+    sync()
+    window.addEventListener('hashchange', sync)
+    return () => window.removeEventListener('hashchange', sync)
+  })
+
+  function navigate(p: string) {
+    location.hash = '#/' + p
+  }
+</script>
+
+<div class="app">
+  <nav class="sidebar">
+    <div class="logo">Oikos</div>
+    <button class="nav-btn" onclick={() => { newChat(); navigate('chat') }}>
+      <span class="nav-icon">✚</span>
+      <span>New</span>
+    </button>
+    <button class="nav-btn" class:active={page === 'chat'} onclick={() => navigate('chat')}>
+      <span class="nav-icon">💬</span>
+      <span>Chat</span>
+    </button>
+    <button class="nav-btn" class:active={page === 'sessions'} onclick={() => navigate('sessions')}>
+      <span class="nav-icon">📋</span>
+      <span>Sessions</span>
+    </button>
+
+    <div class="spacer"></div>
+
+    <button class="drawer-toggle" onclick={() => drawerOpen = !drawerOpen}>
+      Chat {drawerOpen ? '▼' : '▲'}
+    </button>
+  </nav>
+
+  <main class="main">
+    {#if page === 'chat'}
+      <Chat />
+    {:else if page === 'sessions'}
+      <Sessions />
+    {:else}
+      <Chat />
+    {/if}
+  </main>
+
+  {#if drawerOpen}
+    <aside class="drawer" transition:slide={{ axis: 'x' }}>
+      <Chat />
+    </aside>
+  {/if}
+</div>
+
+<style>
+  .app {
+    display: flex;
+    height: 100vh;
+    overflow: hidden;
+  }
+
+  .sidebar {
+    width: 56px;
+    background: var(--bg-surface);
+    border-right: 1px solid var(--border);
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    padding: 0.75rem 0;
+    gap: 0.5rem;
+  }
+
+  .logo {
+    font-size: 1.25rem;
+    font-weight: 700;
+    color: var(--accent-blue);
+    margin-bottom: 0.5rem;
+    user-select: none;
+  }
+
+  .nav-btn {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 2px;
+    padding: 0.5rem;
+    border: none;
+    background: none;
+    color: var(--text-muted);
+    font-family: inherit;
+    font-size: 0.625rem;
+    cursor: pointer;
+    border-radius: 6px;
+    width: 44px;
+    transition: background 0.15s, color 0.15s;
+  }
+
+  .nav-btn:hover {
+    background: var(--bg-hover);
+    color: var(--text);
+  }
+
+  .nav-btn.active {
+    background: var(--bg-active);
+    color: var(--accent-blue);
+  }
+
+  .nav-icon {
+    font-size: 1rem;
+  }
+
+  .spacer {
+    flex: 1;
+  }
+
+  .drawer-toggle {
+    border: none;
+    background: none;
+    color: var(--text-muted);
+    font-family: inherit;
+    font-size: 0.625rem;
+    cursor: pointer;
+    padding: 0.5rem;
+  }
+
+  .drawer-toggle:hover {
+    color: var(--text);
+  }
+
+  .main {
+    flex: 1;
+    overflow: hidden;
+    display: flex;
+    flex-direction: column;
+  }
+
+  .drawer {
+    width: 380px;
+    border-left: 1px solid var(--border);
+    background: var(--bg);
+    overflow: hidden;
+    display: flex;
+    flex-direction: column;
+  }
+</style>