Detect SQLite/BigQuery/Postgres/SQL Server; move secret-manager to saas

[nielsbosma]

Implements five database-detector suggestions from src/.review/. All changes are in data/detectors/database.yml (embedded, auto-loaded).

Changes

• SQLite (sqlite-database-missed.md): extended sqlite deps with NuGet (Microsoft.EntityFrameworkCore.Sqlite, Microsoft.Data.Sqlite[.Core], System.Data.SQLite, sqlite-net-pcl), depPrefix for SQLitePCLRaw., pypi aiosqlite, and an EF Core nuget regex.
• BigQuery (bigquery-database-not-detected.md): added depPrefix Google.Cloud.BigQuery (nuget) to the existing gcp.bigquery entry, surfacing the .NET provider.
• Postgres (postgres-database-missed.md): extended postgresql deps with Go drivers (jackc/pgx/v5, pgx/v4, pgconn, lib/pq) and async-Rust drivers (tokio-postgres, bb8-postgres, deadpool-postgres, postgres-protocol, sqlx-postgres).
• SQL Server (sqlserver-database-not-detected.md): extended the existing mssql entry with NuGet (Microsoft.EntityFrameworkCore.SqlServer, Microsoft.Data.SqlClient, System.Data.SqlClient, Dapper.SqlBuilder), Go/Rust/pypi drivers (go-mssqldb, microsoft/go-mssqldb, tiberius, pyodbc, pymssql), and an EF Core SqlServer nuget regex.
  • DEFERRED: the suggestion's primary signal for the reviewed repo (vinijmoura/Azure-DevOps, which has no manifests — only 38 raw .sql files) is a T-SQL content-sniff. That requires adding RequiresContent/content-sniff support to the tech RuleEngine (only InfraScanner has it today); deferred to avoid a half-working engine change. The dep/files-based detection above is implemented and lands SQL Server for any repo with a real .NET/Go/Rust/pypi SQL Server dependency.
• Secret Manager re-categorization (secret-manager-miscategorized-as-database.md): moved gcp.secretmanager, scaleway.secretmanager, aws.secretsmanager, and hashicorp_vault from category: database to category: saas (existing category) so secrets/config stores stop polluting the db: hash slot.

Testing

dotnet build clean; dotnet test 95/95 passed (baseline 95). rulesLoaded unchanged at 740 (existing entries extended, no rules added/removed).

Snapshots

Updated next-dotnet-monorepo.verified.yaml: SQL Server now correctly surfaces from Microsoft.EntityFrameworkCore.SqlServer (new MS SQL database technology row) — expected diff, accepted.