Add SQLite synchronous connection string option

[AhmedSadek10]

• Add SqliteSynchronousMode and connection string support
• Apply PRAGMA synchronous when opening connections
• Add builder and connection tests

Fixes #38769

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        Fixes #bugnumber

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[AhmedSadek10]

@dotnet-policy-service agree

[Copilot]

Pull request overview

Adds configurable SQLite synchronous modes through connection strings and applies them when connections open.

Changes:

• Adds SqliteSynchronousMode and builder support.
• Applies PRAGMA synchronous during connection opening.
• Adds API baseline and unit-test coverage.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
SqliteSynchronousMode.cs	Defines supported synchronous modes.
SqliteConnectionStringBuilder.cs	Adds the Synchronous option.
SqliteConnection.cs	Applies the configured pragma.
Microsoft.Data.Sqlite.Core.baseline.json	Records the new public API.
SqliteConnectionTest.cs	Tests modes on non-pooled connections.
SqliteConnectionStringBuilderTest.cs	Tests builder parsing and serialization.

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