feat(bindings): put_documents / add_documents across python, nodejs, wasm, ruby, php (#866)

[mosuka]

Summary

Exposes the batch ingestion API (#551 PR-4, the campaign's final PR) in all five language bindings, on top of the merged Engine::put_documents / add_documents.

Each binding gains put_documents / add_documents (putDocuments / addDocuments in the camelCase hosts), taking a list of (id, document) pairs — the most direct mirror of the core Vec<(String, Document)> signature and the natural batched form of each binding's existing singular put_document(id, doc). Semantics carry through from the core: sequential in-order application, one WAL fsync per batch, duplicate-id dedup within a put batch (last wins), chunk accumulation for add, and fail-fast with the applied prefix left in place (retrying is idempotent). Each binding's converter names the offending position on a malformed entry, and an empty batch is a no-op.

Binding	Method shape	Notes
Python	put_documents([(id, dict), ...])	iterable of (str, dict) pairs
Node.js	putDocuments([[id, obj], ...])	Vec<(String, Value)> napi tuple marshalling; index.d.ts regenerated
wasm	putDocuments([[id, obj], ...])	JS array via serde_wasm_bindgen; .d.ts regenerated
Ruby	put_documents([[id, hash], ...])	manual define_method registration added
PHP	putDocuments([[$id, $doc], ...])	nested-array marshalling

The BatchIngest error surfaces message-only through each binding's existing error mapper (the message already carries failed_index / failed_id / applied via Display); no new host exception types.

Verification (real runtime tests, not just compile)

• Python — maturin develop + pytest: 4/4 (test_batch_ingest.py: empty no-op, apply+dedup, chunk accumulation, malformed-entry position).
• Node.js — napi build + vitest: 58/58 (3 new in batch_ingest.spec.mjs); regenerated index.d.ts carries both methods.
• Ruby — rake compile + minitest: 4/4 (test_batch_ingest.rb, incl. ArgumentError naming documents[1]).
• PHP — cargo build --release + phpunit: batch tests green (LaurusTest.php).
• wasm — cargo build --target wasm32-unknown-unknown and wasm-pack build --target web succeed; putDocuments / addDocuments present in the regenerated pkg/*.d.ts. (This binding has no runtime test harness — build-test only, consistent with the rest of the wasm suite.)
• fmt / clippy 1.95 + 1.97 across all four host bindings + wasm-target clippy clean; markdownlint clean on all 10 updated api_reference.md (en+ja × 5).

Generated artifacts (laurus-nodejs/index.d.ts, laurus-wasm/pkg/) are git-ignored, so they are regenerated by each binding's build rather than committed.

Docs

docs/{src,ja/src}/laurus-{python,nodejs,wasm,ruby,php}/api_reference.md: put_documents / add_documents rows (or headings for wasm) with the pair-list shape and fail-fast/no-rollback semantics.

Closes #866. Refs #551 (final PR of the batch-ingestion campaign; the #551 umbrella is closed during wrap-up once PR-3 (#865) and this PR are both merged).