docs: document the differentiating layer (regime/journal/committee)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016DvdRZkyCy9NJpHYDdPqmS

README.md

@@ -56,6 +56,15 @@ Alpaca's clock, then per account applies `execution/guardrails.py` (position/day
 buying-power) and places **GTC bracket** orders (marketable-limit entry so stop/take legs survive
 multi-day holds).
 
+### The differentiating layer
+- **Market regime snapshot** — SPY trend / VIX / sector momentum computed in code each night and
+  injected into every agent's kickoff (shared ground truth).
+- **Self-learning journal** — each agent sees its own past picks marked-to-market before
+  researching; losses and wins become explicit lessons.
+- **AI Investment Committee** — a Chief-Risk-Officer LLM pass reviews the whole book after
+  research and issues per-pick verdicts (APPROVE / REDUCE / VETO with reasons). The memo lands in
+  the Reports tab and the morning executor **enforces** the verdicts.
+
 ## Automate it (America/Chicago)
 - **00:00–07:00** research (~2.3 hr/agent), machine woken at **23:55**.
 - **08:30** execution (= 09:30 ET open; gated on Alpaca's clock, never local time).