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>

plans/2026-07-08-control-room-webui.md

@@ -4,6 +4,16 @@
 `signal.acked`/`signal.resolved`/`signal.muted` and `relationship.created`/
 `relationship.ended` API calls don't emit `observability.Event`, and
 trusted-proxy header auth for Authentik was never added to `combinedAuth`).
+**Superseded (2026-07-12):** the embed architecture below (`go:embed
+all:web/dist`, served at `/ui/`) was removed —
+[2026-07-12-wails-desktop-app.md](2026-07-12-wails-desktop-app.md) Phase 0
+separates the SPA from the `oikos` binary into a standalone static build,
+served at `/` (no `/ui/` prefix), talking to the API over bearer-token
+auth (the dev-open bypass mentioned nowhere in this plan was also removed).
+The trusted-proxy-header gap noted above is moot under the new model — every
+route requires a real bearer token regardless of what's in front of it. M1-M3
+and the SPA/component work below are unaffected; only the packaging and auth
+sections are stale.
 N0-N3 (Nomos amendment: chat home + sessions), M1
 (dashboard/summary, Overview, Entities table, live event feed, shadcn-svelte
 component system), M2 (Operations ledger with approve/deny + cancel, Signals