feat(di)!: remove 11 throwing DI-builder stub methods

[AbongileBoja]

Summary

4.0 BREAKING — Phase 3b of v4 release. Closes the 3.x deprecation shipped in #77. Every removed method shipped on the public surface only to throw NotImplementedException; all 11 carried [Obsolete(error: true)] for the 3.x line. ApiCompat reports CP0001 (member removed) on each.

Removed

Builder	Method	Replacement
AuditingBuilder	LogAllQueries()	wire your own IAuditLogger via WithAuditing(a => a.UseLogger(myLogger))
AuditingBuilder	TrackChanges()	implement change tracking inside your IAuditLogger
AuditingBuilder	EnableEncryption()	encrypt entries inside your IAuditLogger using IEncryptionProvider
AuditingBuilder	UseDatabase(string)	wire a database-backed IAuditLogger
AuditingBuilder	RetentionDays(int)	use IAuditMaintenance.PurgeOldLogsAsync on a schedule
CachingBuilder	EnableCompressionForLarge(int)	wrap ICacheProvider with a compressing decorator (e.g. Scrutor Services.Decorate)
MonitoringBuilder	EnableOpenTelemetry()	call Services.AddOpenTelemetry() directly on the builder's Services property
MonitoringBuilder	EnableHealthChecks()	call Services.AddHealthChecks() directly on the builder's Services property
PerformanceBuilder	EnableQueryCaching()	use WithCaching(c => c.UseMemoryCache()) and compose your query path
PerformanceBuilder	OptimizeExpressions()	no replacement — handled by EF Core / IQueryable providers
SecurityBuilder	RotateKeysEvery(int)	implement key rotation at the storage layer (decrypt with old, re-encrypt with new)

Also removed: AuditingBuilder class-level <remarks> block telegraphing the removal (its purpose is served).

Tests

7 throw-asserting tests removed as planned (6 in IndividualBuildersTests, 1 in QuerySpecBuilderTests):

• CachingBuilder_EnableCompressionForLarge_Throws_NotImplemented
• PerformanceBuilder_EnableQueryCaching_Throws_NotImplemented
• PerformanceBuilder_OptimizeExpressions_Throws_NotImplemented
• SecurityBuilder_RotateKeysEvery_Throws_NotImplemented
• AuditingBuilder_AllStubs_Throw_NotImplemented
• MonitoringBuilder_AllStubs_Throw_NotImplemented
• WithMonitoring_StubsThrowAtConfigTime

Now-orphaned AssertReflectiveThrows helper deleted alongside.

Local verification

• dotnet build -c Release -p:QUERYSPEC_SKIP_SIGN=true — 0 errors
• dotnet test -c Release — 720 unique tests green across net8.0/9.0/10.0 (was 727; 7 removed as planned)

Phase context

• Phase 1 ✓ feat(analyzers): ship QuerySpec.Analyzers package with QSPEC0001/2/3 diagnostics and code fixes #153 (Analyzers)
• Phase 2 ✓ feat(core)!: remove 3.x deprecations GeoLocation/AdvancedFilterExpression/ICacheProvider #154 (deprecation removals)
• Phase 3a ✓ feat(efcore)!: convert QuerySpecExpressionTranslator to static class #155 (translator → static class)
• Phase 3b ← this PR (Remove obsolete DI-builder stub methods in 4.0 #139)
• Phase 3c Remove obsolete IEncryptionProvider.RotateKeyAsync overloads in 4.0 #138 (RotateKeyAsync removal)
• Phase 4 release-engineer — v4.0.0

Closes #139
Refs #77