feat(web): split SPA from oikos binary, require auth on every route

Phase 0 of plans/2026-07-12-wails-desktop-app.md. The control-room SPA
is no longer embedded (web/embed.go deleted); it's a standalone static
build served separately (make ui / make deploy-ui). The api process
adds CORS and drops the dev-open auth bypass — every route now needs a
real bearer token, including SSE (?token= query param, EventSource
can't set headers) and api's own /agent proxy to nomos (previously
unauthenticated by omission).

nomos was an unauthenticated client of api's /mcp and approval-decision
endpoints; closing dev-open would have broken it, so it now sends
Authorization: Bearer $OIKOS_MCP_BEARER_TOKEN on every call back to api.

SPA gets a runtime config module (config.ts) and a Config.svelte
first-launch/reconfigure page, reachable afterwards via a "Connection"
entry in the sidebar footer. Every fetch() in api.ts routes through
fetchWithAuth so the same build works same-origin (browser prod, Vite
dev proxy) or cross-origin (future Wails webview, remote access).

Six gaps found against the plan and the live Caddy topology while
implementing — documented in the plan's "Plan review" section, most
notably: api's own /agent mount was never behind combinedAuth (fixed),
and production's Authentik forward-auth needs a bearer-token bypass for
API routes that this repo's Caddyfile.oikos reference copy now has, but
the real dtoro/caddy-conf deploy does not yet.

Verified live: cross-origin static SPA + API, CORS, bearer auth, SSE
query-token auth, and localStorage persistence all confirmed working
in-browser. Full Go test suite and npm run build pass with no
regressions against the pre-change baseline.

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

web/vite.config.ts

@@ -2,9 +2,25 @@ import { svelte } from '@sveltejs/vite-plugin-svelte'
 import tailwindcss from '@tailwindcss/vite'
 import { defineConfig } from 'vite'
 
+// Injects OIKOS_API_TOKEN into proxied /api requests in dev — the API no
+// longer has a dev-open bypass (plans/2026-07-12-wails-desktop-app.md 0.4),
+// so `OIKOS_API_TOKEN=dev-token npm run dev` needs this to reach it.
+function authProxy(target: string, rewrite?: (path: string) => string) {
+  return {
+    target,
+    ...(rewrite ? { rewrite } : {}),
+    configure: (proxy: any) => {
+      proxy.on('proxyReq', (proxyReq: any) => {
+        const token = process.env.OIKOS_API_TOKEN
+        if (token) proxyReq.setHeader('Authorization', `Bearer ${token}`)
+      })
+    }
+  }
+}
+
 export default defineConfig({
   plugins: [tailwindcss(), svelte()],
-  base: '/ui/',
+  base: '/',
   resolve: {
     alias: { $lib: '/src/lib' }
   },
@@ -14,14 +30,11 @@ export default defineConfig({
   },
   server: {
     proxy: {
-      '/api': 'http://localhost:8090',
+      '/api': authProxy('http://localhost:8090'),
       // Production Caddy strips /agent before forwarding to nomos
       // (compose/caddy/Caddyfile.oikos handle_path /agent/*); match that
       // here so dev and prod agree on nomos's actual route paths.
-      '/agent': {
-        target: 'http://localhost:8092',
-        rewrite: (path) => path.replace(/^\/agent/, '')
-      }
+      '/agent': authProxy('http://localhost:8092', (path) => path.replace(/^\/agent/, ''))
     }
   }
 })