Add result-verified QuestDB adapter

[frahlg]

Summary

• validate the portable summary, CSV header, counts, CRC32, and every numeric point field
• pin summary.txt and points.csv with SHA-256 from validation through import
• refuse a QuestDB volume that already contains any table before creating or writing data
• store every point through ILP/HTTP with valid time as QuestDB's designated timestamp
• wait for the exact visible row count, then verify site-0 grid count/sum/min/max with SAMPLE BY 5m ALIGN TO FIRST OBSERVATION
• report the stored-revision subset, image, settings, timings, checksums, durability limit, and adapter gaps in one JSON line
• run the Python unit tests on Ubuntu and macOS CI

Real QuestDB 9.4.3 checks

Pinned image: questdb/questdb:9.4.3@sha256:3fd139f9f16015afc1b064fe4591b271be26cdec10315415e5511e9d80a5919e

• unaligned start 1767225601234567: 9,438 visible rows, 288 exact buckets, result CRC32 82607103
• standard seven-day bundle: 65,958 visible rows, 2,016 exact buckets, result CRC32 cc32df51
• every stored field was non-null on all 65,958 standard rows; the live schema matched the declared TIMESTAMP, LONG, and VARCHAR types
• a second run against the same volume stopped before ingest
• a changed query bucket fails result verification

The query uses [first,last), so it excludes the generator's final closing point. It uses ALIGN TO FIRST OBSERVATION; it does not round the start with WITH OFFSET.

Tests

• python3 -m unittest -v bench.adapters.test_questdb
• cargo fmt --all -- --check
• cargo clippy --all-targets --all-features --locked --offline -- -D warnings
• cargo test --all-targets --all-features --locked --offline
• cargo test --doc --all-features --locked --offline
• emulator build, fmt, Clippy, and all-target tests with --locked --offline
• docker compose -f bench/compose.yml config --quiet

Scope

QuestDB stores all portable point rows and the three revision times. This adapter verifies only site-0 grid actuals. Catalog import, plan-record import, and a DST calendar query remain not_implemented; this does not claim that QuestDB lacks those features. WAL plus ILP/HTTP acknowledgement is not claimed equal to FTWDB sync durability.