Summary

• Centralize constrained SQLite PRAGMA SQL construction for busy timeout, cache size, mmap size, and auto-vacuum paths.
• Route report schema table_info PRAGMA construction through SqliteCommandPolicy.TableInfoPragmaSql.
• Add the Audit raw SQLite CommandText and PRAGMA construction policy #4070 raw SQL/PRAGMA audit classification table and changelog fragment.

Fixes #4070

Validation

• dotnet test tests/CodeIndex.Tests/CodeIndex.Tests.csproj --framework net8.0 --no-restore --filter FullyQualifiedName~DbConnectionPolicyTests -p:UseSharedCompilation=false -p:BuildInParallel=false -m:1
• dotnet run --project tools/CodeIndex.Changelog -- check
• dotnet build CodeIndex.sln --no-restore -p:UseSharedCompilation=false -p:BuildInParallel=false -m:1
• dotnet format CodeIndex.sln --verify-no-changes --no-restore
• dotnet ./src/CodeIndex/bin/Debug/net8.0/cdidx.dll status --check --json
• dotnet ./src/CodeIndex/bin/Debug/net8.0/cdidx.dll search --recipe dogfood-risk-patterns/raw-sql-command-text --path src/ --exclude-tests --count --group-by file --limit 80
• dotnet ./src/CodeIndex/bin/Debug/net8.0/cdidx.dll search --recipe dogfood-risk-patterns/pragma-command --path src/ --exclude-tests --count --group-by file --limit 80
• Codex adversarial review: No blocking/actionable issues found.