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>

internal/httpapi/sse_test.go

@@ -29,6 +29,7 @@ func TestSSEStreamRealtimeDelivery(t *testing.T) {
 
 	// Connect to the stream.
 	req, _ := http.NewRequestWithContext(ctx, "GET", srv.URL+"/api/v1/events/stream", nil)
+	req.Header.Set("Authorization", "Bearer "+testAuthToken)
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		t.Fatalf("connect stream: %v", err)
@@ -60,7 +61,10 @@ func TestSSEStreamRealtimeDelivery(t *testing.T) {
 	// POSTing to the SAME live server (same DB → NOTIFY the listener sees).
 	time.Sleep(300 * time.Millisecond)
 	payload, _ := json.Marshal(map[string]any{"slug": "service:sse-rt", "type": "service", "name": "sse-rt"})
-	cResp, err := http.Post(srv.URL+"/api/v1/entities", "application/json", bytes.NewReader(payload))
+	createReq, _ := http.NewRequestWithContext(ctx, "POST", srv.URL+"/api/v1/entities", bytes.NewReader(payload))
+	createReq.Header.Set("Content-Type", "application/json")
+	createReq.Header.Set("Authorization", "Bearer "+testAuthToken)
+	cResp, err := http.DefaultClient.Do(createReq)
 	if err != nil {
 		t.Fatalf("trigger create: %v", err)
 	}