fix: harden PostgreSQL failure boundaries

[smiggleworth]

Summary

• observe every checked-out PostgreSQL client and normalize socket failures instead of allowing unhandled process events
• discard failed clients and preserve the original failure across best-effort rollback cleanup
• cap insertMany and upsertMany chunks by both configured rows and PostgreSQL's 65,535 bind-parameter limit
• add real PostgreSQL connection-kill and 70-column batch regressions

Linked issues

Closes #15
Closes #16

TDD

• Red 26f5b31: the child process crashes on unhandled 57P01; the real 70,000-bind insert fails with PostgreSQL 08P01; generated insert/upsert queries each contain all 70,000 values.
• Green 488412d: checked-out client observation converts the error to a catchable connection DatabaseError, while protocol-aware batching produces two safe statements for each bulk operation.

Guardrails

• real child process with pg_terminate_backend() during an idle transaction
• fast listener lifecycle and normalization unit test
• deterministic exact parameter-count assertions for insert and upsert
• real 70-column, 1,000-row insert and upsert
• PostgreSQL 16, 17, and 18 hosted integration matrix

Acceptance audit

• Every acceptance criterion in Dead connection mid-transaction crashes the entire process instead of rejecting cleanly #15 and insertMany/upsertMany chunk by row count, silently overflowing Postgres's parameter limit on wide tables #16 is checked with evidence.
• Full local release gate passes: 41 unit tests, coverage gates, types, build, performance, publint, and package checks.
• Full local PostgreSQL 18 suite passes all 6 tests, including the real failure/scale regressions.
• Runtime dependency audit reports zero vulnerabilities.
• Exact-head hosted package CI and PostgreSQL 16/17/18 matrix pass.
• Release @askrjs/orm@0.0.2 from the exact squash merge.
• Clean registry-only consumer proof.

Local verification

• npm run check
• ASKR_ORM_TEST_DATABASE_URL=... npm run test:integration
• npm audit --omit=dev

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[smiggleworth]

Release closure:

• PR fix: harden PostgreSQL failure boundaries #17 squash-merged as bf6d7fd057855cbcc8e726136b0dd88bf686dd56.
• Publish run 31903111492 passed the full package and PostgreSQL 16/17/18 gates before publishing: https://github.com/askrjs/askr-orm/actions/runs/31903111492
• Annotated tag v0.0.2 resolves to the exact squash commit.
• npm serves @askrjs/orm@0.0.2 with integrity sha512-B+JJ7B8zFVZo2yPoQyEv0xcnfb/rtpuvDC1Et8LBu3c879v1gvCvedsl6nfLnnUTj9RPiwLcuPlTaUH0dMnjPQ==.
• A clean registry-only consumer connected the published package to PostgreSQL 18, terminated a checked-out transaction backend, caught DatabaseError { category: "connection", code: "57P01" }, then inserted and upserted all 1,000 rows of a 70-column table.
• The clean consumer reported zero runtime audit vulnerabilities. Its temporary PostgreSQL container was stopped and removed after verification.