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>

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build webhook test test-db lint generate generate-check dev migrate seed export clean tidy
+.PHONY: build webhook test test-db lint generate generate-check dev migrate seed export clean tidy ui deploy-ui
 
 BINARY := oikos
 GO ?= go
@@ -45,6 +45,15 @@ export:
 dev:
 	docker compose --profile dev up -d
 
+# The SPA is a standalone static build, no longer embedded in the oikos
+# binary (plans/2026-07-12-wails-desktop-app.md 0.1) — deployed separately.
+ui:
+	cd web && npm run build
+
+deploy-ui: ui
+	scp -r web/dist/* mac-mini:/var/www/oikos-ui/
+	ssh mac-mini sudo systemctl reload caddy
+
 clean:
 	rm -f $(BINARY)
 	$(GO) clean -testcache