docs: add EXAA exchange adapter example notebook (05)

[tommed]

Summary

• Adds examples/05_exaa_exchange.ipynb — a comprehensive worked example for the EXAA exchange adapter
• Refreshes executed outputs for notebooks 01–04 (re-run via make execute-notebooks)

Notebook overview

Scenario: Alpenstein Energy GmbH (Vienna) submits to the EXAA Classic day-ahead auction for a dual-zone portfolio:

Asset	Zone	Products
Reisseck II pumped-storage hydro	AT	24 hourly bids (hEXA01–hEXA24)
Bergkamen B CCGT	DE-LU	96 quarter-hourly bids (qEXA01_1–qEXA24_4)
Baseload block	AT	bEXAbase (01-24), divisible
Peak block	AT	bEXApeak (09-20), fill-or-kill

10 sections covering EXAA-specific concepts:

1. Delivery day & CET timezone context (Classic vs Market Coupling deadlines)
2. Hourly supply bids — standard_hourly_product_id, 3-tier hydro merit order
3. Quarter-hourly bids — standard_quarter_hourly_product_id, post-MTU-transition DE-LU
4. Block products — custom BlockProductResolver mapping period hours → exchange names; divisible vs fill-or-kill
5. Order book assembly + bidding_zone_to_control_area zone verification
6. EXAA conversion — composing a mixed ProductIdResolver for portfolios spanning both MTU resolutions
7. Wire-format inspection — model_dump(by_alias=True) with annotated JSON
8. Volume sign convention — assertion-backed demo: SELL = negative, BUY = positive (vs Nord Pool table)
9. Unsupported bid types — LinkedBlockBid raises ValueError; filter_bids resolution pattern
10. Visualisations — hydro price-band profile + block Gantt chart

Test plan

• Notebook executes cleanly end-to-end (make execute-notebooks)
• All assertions pass (sign convention checks)
• No changes to library source code

🤖 Generated with Claude Code

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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