feat: add strict ADJUSTED_LAST history contract

[Pigbibi]

Summary

• add a public strict IBKR daily-history API that makes exactly one ADJUSTED_LAST request
• require a fixed UTC cutoff, explicit duration, exact expected sessions, and fail closed on qualification, request, empty, malformed, duplicate, missing, or unexpected data
• return sanitized request provenance without bars; retain the existing legacy ADJUSTED_LAST -> TRADES helper unchanged

Bounded slice

The preflight found two separate responsibilities, so the authorized work is frozen as ordered slices:

1. This PR: strict ADJUSTED_LAST acquisition request contract (shared predecessor)
2. Sole successor: mandate nonce/replay/atomic single-use/terminal invalidation authority guard

This PR does not implement the successor, a PIT packager, a provider execution path, GCS resources, or any persistence/locking framework.

Tests-first evidence

• RED: focused collection failed because StrictAdjustedHistoryError and fetch_strict_adjusted_historical_price_candles did not exist
• GREEN: 15 passed, 4 subtests passed in tests/test_ibkr_market_data.py
• full suite: 900 passed, 1 skipped, 80 subtests passed
• Ruff: passed
• compileall: passed
• exact three-path scope and dependency-file checks: passed

Authority boundary

• offline fake adapter tests only; no credential/session/provider/API/data call
• no real backtest, promotion acceptance, paper/shadow/live, broker/order/capital action
• no production dependency change