chore(release): bump to 0.0.12; skip-existing on PyPI publish

[eldonm]

Problem

The publish-on-push workflow re-uploads the current package version on every merge to main. Since __version__ stayed at 0.0.11 (already on PyPI), merges #26 and #27 failed the Publish to PyPI job with 400 File already exists ('jvspatial-0.0.11-...'). Test / Benchmarks / Lint all pass — only publish was red.

Fix

• Bump __version__ 0.0.11 → 0.0.12 — releases the postgres translator column-index fix (entity/id/tenant_id hit real indexed columns, not JSONB paths) + the observability env keys from fix(postgres): translate entity/id/tenant_id to real columns; register observability env keys #27.
• skip-existing: true on the pypa/gh-action-pypi-publish step — a merge that doesn't bump the version becomes a no-op success instead of red-X'ing main; a real upload happens only when version.py is bumped.

Test plan

• pre-commit run clean (black, isort, flake8, mypy, detect-secrets).
• On merge: publish uploads 0.0.12; subsequent non-bump merges no-op green.

🤖 Generated with Claude Code

[github-actions]

Benchmark comparison

Threshold: ±25% (informational, does not block merge)

benchmark	baseline (s)	current (s)	delta	status
tests/benchmarks/test_deferred_save_benchmarks.py::test_bench_deferred_save_batched_100	0.050411	0.049226	-2.3%	OK
tests/benchmarks/test_deferred_save_benchmarks.py::test_bench_immediate_save_100	0.049643	0.049553	-0.2%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_batched_saves_500	0.474917	0.472605	-0.5%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_count_empty_query	1.066643	1.002546	-6.0%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_count_filtered	1.155337	1.121882	-2.9%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_find_filtered	0.899911	0.863645	-4.0%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_save_throughput	0.001622	0.001593	-1.7%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_empty	0.342328	0.348949	+1.9%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_fallback_via_regex	0.381869	0.398883	+4.5%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_pushdown	0.390604	0.354373	-9.3%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_find_fallback_via_regex	0.388111	0.398507	+2.7%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_find_pushdown	0.343803	0.357760	+4.1%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_sort_limit_pushdown	0.397770	0.399719	+0.5%	OK