fix: send missing multipart form data fields in create endpoints

[Copilot]

• Fix 1: TorrentsClient.CreateTorrentAsync — add missing add_only_if_cached field to multipart content
• Fix 2: TorrentsClient.AsyncCreateTorrentAsync — add missing add_only_if_cached field to multipart content
• Fix 3: UsenetClient.CreateUsenetDownloadAsync — add missing as_queued and add_only_if_cached fields to multipart content
• Fix 4: UsenetClient.AsyncCreateUsenetDownloadAsync — add missing as_queued and add_only_if_cached fields to multipart content
• Fix 5: Add unit tests verifying these fields are included (Theory with InlineData for true/false)
• Build and test verification (0 warnings, 345 tests pass on net8.0 + net10.0)
• Code review and CodeQL validation passed
• Review feedback 1: Move CreateTorrentAsync_WithAddOnlyIfCached test next to other CreateTorrentAsync tests
• Review feedback 2: UsenetClientTests — verify actual multipart values (not just field names) for CreateUsenetDownloadAsync
• Review feedback 3: UsenetClientTests — verify actual multipart values (not just field names) for AsyncCreateUsenetDownloadAsync

[Copilot]

Pull request overview

Fixes missing multipart form-data fields so TorBox “create” endpoints actually receive add_only_if_cached (torrents + usenet) and as_queued (usenet), aligning the request models with what gets sent over the wire.

Changes:

• Add add_only_if_cached to multipart content in TorrentsClient.CreateTorrentAsync and TorrentsClient.AsyncCreateTorrentAsync.
• Add as_queued and add_only_if_cached to multipart content in UsenetClient.CreateUsenetDownloadAsync and UsenetClient.AsyncCreateUsenetDownloadAsync.
• Add unit tests asserting the new multipart fields are present.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/TorBoxSDK/Main/Torrents/TorrentsClient.cs	Sends add_only_if_cached in multipart for both torrent create endpoints.
src/TorBoxSDK/Main/Usenet/UsenetClient.cs	Sends as_queued + add_only_if_cached in multipart for both usenet create endpoints.
tests/TorboxSDK.UnitTests/Main/Torrents/TorrentsClientTests.cs	Adds coverage for add_only_if_cached being included in multipart requests.
tests/TorboxSDK.UnitTests/Main/Usenet/UsenetClientTests.cs	Adds coverage for as_queued/add_only_if_cached being included in multipart requests.

[Copilot]

These assertions only check that the multipart body contains the field names, but don't verify that the serialized values match the asQueued / addOnlyIfCached inputs. Adding value assertions (ideally tied to each field name) would better protect against regressions like hardcoding the value or swapping the two fields.

Suggested change

	Assert.Contains("as_queued", handler.LastRequestContent);
	Assert.Contains("add_only_if_cached", handler.LastRequestContent);
	string multipartContent = handler.LastRequestContent;
	System.Text.RegularExpressions.Match asQueuedMatch = System.Text.RegularExpressions.Regex.Match(
	multipartContent,
	"name=\"as_queued\"\\r\\n\\r\\n(?<value>[^\\r\\n]+)");
	System.Text.RegularExpressions.Match addOnlyIfCachedMatch = System.Text.RegularExpressions.Regex.Match(
	multipartContent,
	"name=\"add_only_if_cached\"\\r\\n\\r\\n(?<value>[^\\r\\n]+)");
	Assert.True(asQueuedMatch.Success);
	Assert.True(addOnlyIfCachedMatch.Success);
	Assert.Equal(asQueued.ToString().ToLowerInvariant(), asQueuedMatch.Groups["value"].Value.ToLowerInvariant());
	Assert.Equal(addOnlyIfCached.ToString().ToLowerInvariant(), addOnlyIfCachedMatch.Groups["value"].Value.ToLowerInvariant());

[Copilot]

These assertions only check that the multipart body contains the field names, but don't verify that the serialized values match the asQueued / addOnlyIfCached inputs. Adding value assertions (ideally tied to each field name) would better protect against regressions like hardcoding the value or swapping the two fields.

Suggested change

	Assert.Contains("as_queued", handler.LastRequestContent);
	Assert.Contains("add_only_if_cached", handler.LastRequestContent);
	string expectedAsQueuedContent = $"name=\"as_queued\"\r\n\r\n{asQueued.ToString().ToLowerInvariant()}";
	string expectedAddOnlyIfCachedContent = $"name=\"add_only_if_cached\"\r\n\r\n{addOnlyIfCached.ToString().ToLowerInvariant()}";
	Assert.Contains(expectedAsQueuedContent, handler.LastRequestContent);
	Assert.Contains(expectedAddOnlyIfCachedContent, handler.LastRequestContent);

[Copilot]

This new CreateTorrentAsync_* test is placed under the // --- AsyncCreateTorrentAsync --- section header, which makes the file harder to navigate (the other CreateTorrentAsync_* tests are earlier in the file). Consider moving this test next to the existing CreateTorrentAsync tests and/or introducing a // --- CreateTorrentAsync --- section header so the grouping matches the method under test.

[devRael1]

@copilot apply changes based on the comments in this thread

[Copilot]

@copilot apply changes based on the comments in this thread

Applied all three review comments in 8ce0f58:

1. Test placement: Moved CreateTorrentAsync_WithAddOnlyIfCached test next to the other CreateTorrentAsync tests (before ControlTorrentAsync section).
2. Usenet value assertions: Both CreateUsenetDownloadAsync and AsyncCreateUsenetDownloadAsync tests now verify the actual multipart field values (e.g. name=as_queued\r\n\r\ntrue) instead of just checking field names are present.
3. Torrent value assertions: Applied the same value-checking pattern to both torrent AddOnlyIfCached tests for consistency.