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>

docker-compose.yml

@@ -1,6 +1,10 @@
 # Docker Compose for Oikos development
 # Usage: docker compose up -d postgres  (just the DB)
 #        make dev                     (full dev stack)
+#
+# The SPA isn't part of this stack — it's a standalone static build served
+# separately (`make ui`, `npm run dev` in web/), not embedded in the oikos
+# image. See plans/2026-07-12-wails-desktop-app.md 0.1/0.6.
 
 services:
   postgres:
@@ -60,6 +64,10 @@ services:
       OIKOS_API_LISTEN: ":8090"
       OIKOS_ENV: dev
       OIKOS_DEBUG: "true"
+      # No dev-open auth bypass (plans/2026-07-12-wails-desktop-app.md 0.4) —
+      # every request needs this token. nomos uses the same value to call
+      # back into api's /mcp and /api/v1/approvals/*/decision.
+      OIKOS_MCP_BEARER_TOKEN: ${OIKOS_MCP_BEARER_TOKEN:-dev-token}
       OIKOS_NOMOS_AGENT_SLUG: ${OIKOS_NOMOS_AGENT_SLUG:-agent:nomos}
       NOMOS_PROXY_URL: http://nomos:8092
     volumes:
@@ -129,6 +137,9 @@ services:
       OPENROUTER_API_KEY: ${OPENROUTER_API_KEY}
       NOMOS_MODEL: ${NOMOS_MODEL:-deepseek/deepseek-v4-pro}
       DATABASE_URL: postgres://oikos:${OIKOS_DB_PASSWORD:-oikos_dev}@postgres:5432/oikos?sslmode=disable
+      # Must match api's OIKOS_MCP_BEARER_TOKEN above — api's combinedAuth
+      # rejects every request without it now (no dev-open bypass).
+      OIKOS_MCP_BEARER_TOKEN: ${OIKOS_MCP_BEARER_TOKEN:-dev-token}
     ports:
       - "8092:8092"
     stop_signal: SIGTERM