Check log level before logging in hot path

[kvch]

Description

The WAL listener allocated a 3-entry loglib.Fields map without any log-level check could short-circuit it.
This was a waste of allocations if the log level was not debug or trace.

Metric	main (baseline)	this pr	Δ vs main
Time	520.15n	34.88n	−93.29%
Bytes/op	376.0	0.0	−100.00%
Allocs/op	5.000	0.000	−100.00%

Type of Change

Please select the relevant option(s):

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔧 Refactoring (no functional changes)
• ⚡ Performance improvement
• 🧪 Test coverage improvement
• 🔨 Build/CI changes
• 🧹 Code cleanup

Changes Made

• Added IsDebugEnabled() to the loglib.Logger interface and to NoopLogger
• Wrapped the per-event Trace/Debug calls in IsTraceEnabled()/IsDebugEnabled() checks

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• All existing tests pass

Checklist

• Code follows project style guidelines
• Self-review completed
• Code is well-commented
• Documentation updated where necessary

[github-actions]

Merging this branch will decrease overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/xataio/pgstream/pkg/log	0.00% (ø)
github.com/xataio/pgstream/pkg/wal/listener/kafka	66.67% (-2.90%)	👎
github.com/xataio/pgstream/pkg/wal/listener/postgres	95.74% (-2.08%)	👎
github.com/xataio/pgstream/pkg/wal/processor/filter	92.16% (-1.84%)	👎
github.com/xataio/pgstream/pkg/wal/processor/injector	79.28% (-1.45%)	👎
github.com/xataio/pgstream/pkg/wal/processor/search	80.22% (-0.30%)	👎

---

Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/xataio/pgstream/pkg/log/logger.go	0.00% (ø)	13 (+1)	0	13 (+1)
github.com/xataio/pgstream/pkg/wal/listener/kafka/wal_kafka_reader.go	66.67% (-2.90%)	24 (+1)	16	8 (+1)	👎
github.com/xataio/pgstream/pkg/wal/listener/postgres/wal_pg_listener.go	95.74% (-2.08%)	47 (+1)	45	2 (+1)	👎
github.com/xataio/pgstream/pkg/wal/processor/filter/wal_filter.go	92.16% (-1.84%)	51 (+1)	47	4 (+1)	👎
github.com/xataio/pgstream/pkg/wal/processor/injector/wal_injector.go	79.28% (-1.45%)	111 (+2)	88	23 (+2)	👎
github.com/xataio/pgstream/pkg/wal/processor/search/search_batch_indexer.go	71.25% (-0.90%)	80 (+1)	57	23 (+1)	👎

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.