feat: add standalone binlog-to-page correlation API

[ringo380]

Summary

• Add correlate_events() API in new src/binlog/correlate.rs — maps binlog row events (INSERT/UPDATE/DELETE) to tablespace pages via B+Tree PK lookup
• Refactor timeline.rs::correlate_binlog_pages() to use shared helpers (build_column_meta, convert_pk_values), eliminating ~50 lines of duplication
• Add correlate_binlog_events() WASM export for web UI consumption

Closes #178

New API

pub fn correlate_events(
    binlog: &mut BinlogFile,
    ts: &mut Tablespace,
) -> Result<Vec<CorrelatedEvent>, IdbError>

CorrelatedEvent includes: binlog_pos, event_type (Insert/Update/Delete), database, table, page_no, space_id, page_lsn, pk_values, timestamp.

Test plan

• Unit tests for RowEventType, convert_pk_values, build_column_meta
• Integration test: correlate_events returns empty vec for tablespace without SDI
• cargo clippy -- -D warnings — zero warnings
• cargo check --target wasm32-unknown-unknown --no-default-features — WASM compiles
• Full test suite passes

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[ringo380]

Code review

Found 1 issue:

1. Bare numeric event type codes (19, 30, 31, 32) used instead of named constants from src/binlog/constants.rs (CLAUDE.md says "Binlog constants in src/binlog/constants.rs match MySQL binlog_event.h names; other binlog submodules import from there (no local duplicates)")

RowEventType::from_type_code uses raw literals 30, 31, 32, and correlate_events checks type_code == 19 directly. These should import and use TABLE_MAP_EVENT, WRITE_ROWS_EVENT, UPDATE_ROWS_EVENT, DELETE_ROWS_EVENT from crate::binlog::constants.

idb-utils/src/binlog/correlate.rs

Lines 37 to 49 in 420352c

	match code {
	30 => Some(RowEventType::Insert), // WRITE_ROWS_EVENT_V2
	31 => Some(RowEventType::Update), // UPDATE_ROWS_EVENT_V2
	32 => Some(RowEventType::Delete), // DELETE_ROWS_EVENT_V2
	_ => None,
	}
	}
	}
	impl std::fmt::Display for RowEventType {
	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
	match self {
	RowEventType::Insert => write!(f, "INSERT"),

idb-utils/src/binlog/correlate.rs

Lines 157 to 160 in 420352c

	let space_id = match FilHeader::parse(&page0) {
	Some(h) => h.space_id,
	None => return Ok(vec![]),
	};

CLAUDE.md reference: https://github.com/ringo380/idb-utils/blob/420352cb081ae8f04e75424f90e73da968bc1adf/CLAUDE.md#L167