feat: add OpenOptions for partial workbook reading

[Nebu1eto]

Summary

• Add OpenOptions struct (Rust) / JsOpenOptions type (TypeScript) for controlling workbook parsing at open time
• sheet_rows: Limit the number of rows read per sheet (like SheetJS sheetRows). Rows beyond the limit are discarded during parsing for a real performance benefit.
• sheets: Only parse selected sheets by name. Unselected sheets exist in the workbook but contain no data (their XML is skipped entirely).
• max_unzip_size / max_zip_entries: ZIP safety limits to prevent zip bombs. Exceed either limit and the open call returns an error.
• New error variants: ZipSizeExceeded, ZipEntryCountExceeded
• All existing open() / openSync() / openBuffer() / openBufferSync() methods accept an optional options parameter -- fully backward compatible
• Rust: Workbook::open_with_options(path, &opts) and Workbook::open_from_buffer_with_options(data, &opts)
• 17 new Rust tests + 13 new Node.js tests covering all option fields and combinations
• API reference docs updated in both EN and KO

Test plan

• cargo build --workspace passes
• cargo test --workspace passes (1253 core + 178 xml + 7 integration + 1 facade + 5 doc = 1444 total)
• cargo clippy --workspace passes (no warnings)
• cargo fmt --check passes
• pnpm build passes (napi + typecheck + tsdown)
• pnpm vitest run passes (267 tests including 13 new open options tests)
• pnpm biome check . passes
• pnpm tsc --noEmit passes
• No .claude/ files committed

Generated with Claude Code

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[Nebu1eto]

Review finding (blocking): OpenOptions sheets filtering currently swaps unselected worksheets to WorksheetXml::default() during open, and save then writes those empty worksheets back. This makes open_with_options(...).save(...) data-destructive for skipped sheets.

Relevant path: crates/sheetkit-core/src/workbook/io.rs (sheet parse branch that uses WorksheetXml::default(), and full worksheet write path).

Suggested fix: preserve raw XML bytes for unparsed sheets (or forbid save when selective parsing was used) so skipped sheets round-trip without data loss.

[Nebu1eto]

Detailed review notes (blocking):

OpenOptions is a valuable addition, but there is a data-loss path today.

Blocking concern:

• With selective sheet parsing (sheets option), unselected worksheets are replaced by WorksheetXml::default() during open.
• A subsequent save writes those default/empty worksheets back, which destroys data on skipped sheets.

Relevant area:

• crates/sheetkit-core/src/workbook/io.rs (sheet parse branch + normal worksheet serialization path).

Expected behavior for safety:

• Either preserve raw XML bytes for unparsed sheets and round-trip them unchanged, or
• mark workbook as partially loaded and reject save unless explicitly forced.

Please add a regression test for: open_with_options(select subset) -> save -> reopen -> skipped sheet data remains intact.