feat: MySQL CDC GA — type fidelity, bootstrap, cursor chunker, non-integer PKs

[dariomazzitellireplik-coder]

Summary

Graduates MySQL source from BETA → STABLE in v2.5.0. Closes the correctness and UX gaps identified at v2.3.0 (PR #97). After this lands, the README/docs drop the 🧪 Beta badge and the C11 type-roundtrip verify check passes against MySQL sources without --skip C11.

OpenSpec change: mysql-cdc-beta-to-ga.

Highlights

Type fidelity

• Value::UInt64(u64) + DataType::UInt64 for BIGINT UNSIGNED. Previously dbmazz silently wrapped values ≥ 2^63 to negative i64. Sinks map to NUMERIC(20,0) (PG/SF) or LARGEINT (StarRocks).
• Value::Timestamp(micros) replaces the temporary ISO-string shim from PR feat: add MySQL CDC source (BETA) #97 for TIMESTAMP/DATETIME columns. DATETIME(p) microseconds preserved end-to-end (previously the _us parameter was dropped).
• DECIMAL precision/scale propagated from information_schema.columns — was hardcoded Decimal{38,9} regardless of source.

First-run binlog bootstrap (H5)

On a fresh start, SHOW MASTER STATUS is captured before the snapshot worker spawns and persisted as PROVISIONAL. The post-snapshot CDC stream resumes from that point — no more replaying days of binlogs, no hard error if old binlogs were purged. The first commit promotes the row to ACTIVE.

Snapshot performance (M3)

Cursor-based keyset paging replaces MIN(pk)/MAX(pk) + linear partitioning. Each chunk has bounded row count regardless of PK density — sparse distributions no longer produce empty / oversized chunks.

Non-integer PK support (M4)

VARCHAR / CHAR / UUID / BINARY / VARBINARY primary keys now snapshot-able. PkKind::Str uses COLLATE utf8mb4_bin for deterministic byte-wise ordering. Composite PK and no-PK tables are skipped with WARN logs.

Cleanup

• Drop Source::start_replication, checkpoint_position, cleanup — engine uses create_loop exclusively.
• Drop SinkResult::last_position — populated by all three sinks but never consumed.

Migrations (auto, idempotent)

• dbmazz_snapshot_state adds start_pk_text/end_pk_text/pk_kind; relaxes NOT NULL on legacy start_pk/end_pk. Backfills Int-kinded rows.
• dbmazz_checkpoints adds nullable status VARCHAR(16) for PROVISIONAL bootstrap rows.

Verify matrix

Run against dbmazz-mysql:dev built from this branch:

Combo	Result
PG → PG	18/0/0 ✓
PG → StarRocks	17/0/1 ✓ (A4 skip expected)
MySQL → PG	18/0/0 ✓
MySQL → StarRocks	17/0/1 ✓

C11 type-roundtrip now passes 7/7 against MySQL — confirms BIGINT UNSIGNED + DATETIME micros + DECIMAL precision + Value::Timestamp end-to-end.

Static checks

• cargo fmt --all -- --check clean
• cargo clippy --features mysql-source -- -D warnings clean
• cargo clippy -- -D warnings clean
• cargo test --features mysql-source --lib → 270 passed / 0 failed
• cargo test --lib → 158 passed / 0 failed

Test plan

• cargo fmt --all -- --check
• cargo clippy --features mysql-source -- -D warnings
• cargo clippy -- -D warnings
• cargo test --features mysql-source
• cargo test
• ez-cdc verify — PG → PG: 18/0/0
• ez-cdc verify — PG → SR: 17/0/1
• ez-cdc verify — MySQL → PG: 18/0/0 (C11 7/7)
• ez-cdc verify — MySQL → SR: 17/0/1 (C11 7/7)
• ez-cdc verify MySQL → Snowflake (deferred — no SF creds in dev-stack)
• H5 bootstrap integration test against a fresh MySQL with concurrent INSERTs (deferred — #[ignore]'d test in tasks.md)

Cross-repo

After merge: open a sister PR on ez-cdc-cli README to drop the historical "C11 expected to FAIL with MySQL" disclaimer (already noted in v0.5.3 CHANGELOG that this is resolved with dbmazz ≥ 2.4.0; v2.5.0 makes it fully accurate without the --skip C11 recommendation).

Breaking changes (in-tree only)

• Value::UInt64 and DataType::UInt64 are new variants — sinks updated in lockstep.
• Source trait method removals — PG/MySQL impls updated in lockstep.
• SinkResult::last_position removal — sink impls updated in lockstep.
• No out-of-tree implementors of these traits / structs.