module: Complete Projects SDK surface

[teesofttech]

Goal

Finish project management to prerelease quality.

Scope

• Move ProjectService onto the shared authenticated client/session foundation.
• Use site LUID based URLs and X-Tableau-Auth consistently.
• Validate create/update/delete payloads against Tableau REST API expectations.
• Add support for parent projects and owner fields where applicable.
• Add pagination support for list operations.

Tests

• Unit tests for every public method.
• Unit tests for URL construction, auth headers, payload shape, response parsing, optional fields, and error paths.
• Integration tests for safe read operations.
• Mutating integration tests for create/update/delete project must be opt-in and clean up resources.

Docs / Examples

• Add examples for listing, creating, updating, and deleting projects.

Release

When done, run build/test/pack and publish the next NuGet prerelease.