fix(db): quiet routine timing logs and prepare 0.2.1

[eldonm]

Routine db.find and other successful operation timings currently emit at INFO, flooding application logs when observability is enabled. Emit these timings at DEBUG so applications can opt into detailed telemetry without losing important warnings.

Slow operations retain WARNING. Fast failed operations now also use WARNING with a FAILED prefix, preserving failure visibility when routine timings are filtered. Structured fields, slow-query thresholds, exception propagation, metrics, and operation counters remain unchanged. Update the observability guide and technical specification, and record the fix in the 0.2.1 changelog. Bump the single-source package version to 0.2.1.

Validation:

• Reproduced the old behavior with failing regression tests before the fix.
• Database and observability suites: 573 passed, 70 skipped (optional backend/integration lanes unavailable locally).
• All pre-commit checks passed, including formatting, lint, mypy, and secret detection.
• Built the 0.2.1 wheel and verified both METADATA and its packaged version.py report 0.2.1.
• After the version bump, relevant database/observability regression tests passed: 40 passed, 1 skipped.
• Coverage verifies quiet INFO-level get/find calls with metrics intact, DEBUG structured fields, slow-query warnings, failure warnings and propagated exceptions, and residual-scan telemetry.

Applications that collect routine operation timing logs must enable DEBUG for jvspatial.db.observable and their handler. The version bump prepares 0.2.1; merging to main triggers the existing release workflow. Publication has not yet been verified.

[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	0.022033	0.027640	+25.4%	REGRESSION (+25.4%)
tests/benchmarks/test_deferred_save_benchmarks.py::test_bench_immediate_save_100	0.022288	0.027342	+22.7%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_projection_capture[hierarchy]	0.003766	0.005057	+34.3%	REGRESSION (+34.3%)
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_projection_capture[ontology]	0.004022	0.005304	+31.9%	REGRESSION (+31.9%)
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_projection_capture[relationships]	0.003781	0.005257	+39.1%	REGRESSION (+39.1%)
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_rich_projection_capture[hierarchy]	0.003514	0.004346	+23.7%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_rich_projection_capture[ontology]	0.003319	0.004139	+24.7%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_rich_projection_capture[relationships]	0.003308	0.004217	+27.5%	REGRESSION (+27.5%)
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_batched_saves_500	0.404674	0.466547	+15.3%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_count_empty_query	0.001994	0.002002	+0.4%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_count_filtered	0.094640	0.105151	+11.1%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_find_filtered	0.096290	0.102572	+6.5%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_save_throughput	0.001503	0.001782	+18.6%	OK
tests/benchmarks/test_postgres_benchmarks.py::test_bench_postgres_find_many_bulk	0.001012	0.001088	+7.6%	OK
tests/benchmarks/test_postgres_benchmarks.py::test_bench_postgres_traverse_depth	0.000639	0.000683	+6.9%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_empty	0.000233	0.000309	+32.5%	REGRESSION (+32.5%)
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_fallback_via_regex	0.028622	0.031094	+8.6%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_pushdown	0.001327	0.001564	+17.8%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_find_fallback_via_regex	0.028730	0.030286	+5.4%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_find_pushdown	0.000397	0.000464	+16.8%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_sort_limit_pushdown	0.002377	0.002741	+15.3%	OK

[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	0.022033	0.016616	-24.6%	OK
tests/benchmarks/test_deferred_save_benchmarks.py::test_bench_immediate_save_100	0.022288	0.016012	-28.2%	IMPROVED (-28.2%)
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_projection_capture[hierarchy]	0.003766	0.002961	-21.4%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_projection_capture[ontology]	0.004022	0.003064	-23.8%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_projection_capture[relationships]	0.003781	0.003141	-16.9%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_rich_projection_capture[hierarchy]	0.003514	0.002626	-25.3%	IMPROVED (-25.3%)
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_rich_projection_capture[ontology]	0.003319	0.002524	-24.0%	OK
tests/benchmarks/test_graph_projection_benchmarks.py::test_warm_rich_projection_capture[relationships]	0.003308	0.002509	-24.2%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_batched_saves_500	0.404674	0.465665	+15.1%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_count_empty_query	0.001994	0.001540	-22.8%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_count_filtered	0.094640	0.072841	-23.0%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_find_filtered	0.096290	0.074592	-22.5%	OK
tests/benchmarks/test_jsondb_benchmarks.py::test_bench_jsondb_save_throughput	0.001503	0.001529	+1.7%	OK
tests/benchmarks/test_postgres_benchmarks.py::test_bench_postgres_find_many_bulk	0.001012	0.000761	-24.8%	OK
tests/benchmarks/test_postgres_benchmarks.py::test_bench_postgres_traverse_depth	0.000639	0.000475	-25.6%	IMPROVED (-25.6%)
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_empty	0.000233	0.000175	-24.8%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_fallback_via_regex	0.028622	0.021930	-23.4%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_count_pushdown	0.001327	0.001064	-19.8%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_find_fallback_via_regex	0.028730	0.021658	-24.6%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_find_pushdown	0.000397	0.000305	-23.1%	OK
tests/benchmarks/test_sqlite_benchmarks.py::test_bench_sqlite_sort_limit_pushdown	0.002377	0.001884	-20.7%	OK