ci: add PR check workflow (lint, build, test) before merge to main

feat: distinguish scheduled vs manual agent run triggers in UI

feat: move agent scheduling from GitHub Actions cron to NestJS in-process

fix: show 'manual' triggered_by when agent is dispatched via workflow_dispatch

feat: reschedule paper trader to 8:30 AM, 11:00 AM, 1:45 PM CST

feat: change market analyst trigger to 7:30 AM CST (13:30 UTC)

feat: change market analyst trigger to 8:30 AM CST (14:30 UTC)

feat: change market analyst trigger to 9:00 AM CST (15:00 UTC)

feat: shift paper trader schedule to CST times (+1 hour UTC)

feat: reschedule paper trader to 9:30 AM, 11:30 AM, 2:00 PM CDT

feat: schedule paper trader 3x daily at 9:30, 12:30, 2:45 PM CST

feat: enforce hard buying-power cap and prevent concurrent paper-trader runs

feat: run paper trader every 30 mins during NYSE market hours

Add meaningful workflow names/step labels and keepalive ping workflow

Consolidate all services around root config files

Clean up env vars and fix retrospective last-Sunday check

Add GitHub Actions CI/CD, HF Space deployment, market hours guard, and static serving