Refactor API to use nested sessions/devices routers and fix test infrastructure

- Update API contract to use nested router structure for sessions and devices
  (me.sessions.list, me.devices.getInfo, etc.)
- Update frontend Svelte components to use new nested API paths
- Fix test assertion patterns for consistency (remove async () => wrappers)
- Fix test-db.ts findRepoRoot to use existsSync for directory checking
  (Bun.file().exists() returns false for directories)
- Add ESLint config override for test files to handle expect().rejects patterns

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

db/schema.sql

@@ -1,4 +1,4 @@
-\restrict JcXyipc16dugUGJvd2oDJgA4cUi3A29rdzMF11XH6GPR94bG05YyvDzwhuyfGSd
+\restrict CIj4ub2A9kD8NQM2nKa1cg31hNutT3jXdOch0DnJ2bT48qpQKbe9XxNtViPwfYR
 
 -- Dumped from database version 17.7
 -- Dumped by pg_dump version 17.7
@@ -1084,7 +1084,7 @@ ALTER TABLE ONLY public.user_devices
 -- PostgreSQL database dump complete
 --
 
-\unrestrict JcXyipc16dugUGJvd2oDJgA4cUi3A29rdzMF11XH6GPR94bG05YyvDzwhuyfGSd
+\unrestrict CIj4ub2A9kD8NQM2nKa1cg31hNutT3jXdOch0DnJ2bT48qpQKbe9XxNtViPwfYR
 
 
 --