Split web server process from Ava bot runtime.
Implement a dedicated web service entrypoint (Omni/Web.hs) that runs Omni.Web.Core as its own executable/systemd-deployable unit, and stop booting the web server from Omni/Ava/Core.hs.
Acceptance:
Omni/Web.hs builds as a standalone executable (e.g. web) and serves current Omni web routes.web service for beryllium.Final cutover completed under t-672: ava now runs without in-process web, and standalone web.service now owns port 8079.
Ava verified: implementation present in live tree (file/feature confirmed via inspection). Moving to Verified.
Implemented standalone web service split. Added Omni/Web.hs (out: web), removed web fork from Omni/Ava/Core.hs, and deployed new web.service on beryllium via manifest + push.sh --force. web.service now runs /nix/store/mqxgfdrild8yfbwblky2jrza5sadxyh4-web/bin/web --port 8081 and serves tasks/tag UI (health=ok, /tasks=200). Follow-up t-671 created for /news link/routing alignment on standalone web. Evidence: _/tmp/proof-t-669.md