docs: correct 2026-09-01 expiry report P&L to broker truth

[kunalrbhatia]

Summary

Correct the 2026-09-01 NIFTY expiry report P&L to broker-verified truth.

Why

The initial automated report (PR #116) showed +₹2046.85 PROFIT, but broker GET_POSITIONS shows the day was a LOSS. Root cause: the report generator whitelists symbols from positions.json, which was pruned/rebuilt mid-session (11:59 reconcile) — so the algo-traded 24000 CE (−6835.40) / 24000 PE (+4712.50) pair was excluded from the P&L. Adding those back:

• Algo (smart-api) P&L: −₹76.05 (≈ breakeven)
• Full NIFTY01SEP book: −₹1164.80 (includes niftyicif foreign legs −₹1088.75)

Change

• Rewrote expiry-reports/expiry-NIFTY-2026-09-01.md with all 14 broker legs (not just the 8 whitelisted), corrected totals, and a prominent CORRECTION note.
• Prettier-formatted.

Verification

• Broker GET_POSITIONS (16:26 IST) per-leg values used verbatim.
• Sum of all 14 legs = −₹1164.80 = broker total (exact match).
• Algo subset (10 symbols) = −₹76.05.

Follow-up

• The report generator's positions.json-whitelist gap (pruned legs missed) needs a fix: use GET_POSITIONS for the session's expiry + known algo symbols from the order book, not just current positions.json. Tracking as a separate item.