Diagnostics: attribute validation (ConnectorName, OperationName, ConnectorTriggerMetadata)

[daviburg]

Summary

Validate [ConnectorTriggerMetadata], [ConnectorOperation], and related attribute arguments against the SDK index.

Parent: #38 | Depends on: #39 (diagnostics infrastructure)

Diagnostics

Small effort

Code	Severity	Diagnostic	Detection
CSDK001	Error	ConnectorName value doesn't match any constant in ConnectorNames class	Compare attribute string value against SdkIndex.ConnectorNameConstants
CSDK002	Warning	Possible typo in ConnectorName — did you mean ""X""?	Levenshtein distance <= 2 against SdkConstant.Value list
CSDK003	Warning	ConnectorName has wrong casing (e.g., ""Office365"" vs ""office365"")	Case-insensitive match exists but case-sensitive doesn't
CSDK004	Error	[ConnectorTriggerMetadata] missing required ConnectorName property	Check attribute constructor/named args for presence
CSDK005	Error	[ConnectorTriggerMetadata] missing required OperationName property	Check attribute constructor/named args for presence
CSDK006	Warning	[ConnectorTriggerMetadata] applied to non-async method	Check method signature has async modifier or returns Task/Task<T>

Medium effort

Code	Severity	Diagnostic	Detection
CSDK007	Error	OperationName doesn't exist for connector ""X""	Lookup SdkIndex.TriggerOperationsByConnector[connectorName], validate operation exists
CSDK008	Warning	OperationName specified without ConnectorName — cannot validate	Detect presence of OperationName but missing ConnectorName
CSDK009	Warning	[ConnectorOperation] attribute value doesn't match any known operation for this connector	Cross-reference operation method discovery from SdkDynamicOperationsDiscovery

Implementation Notes

• Use Roslyn SemanticModel.GetDeclaredSymbol() to get method symbols, then inspect GetAttributes()
• Extract attribute argument values via AttributeData.ConstructorArguments and NamedArguments
• SdkIndex.ConnectorNameConstants already provides the full list of valid connector names
• SdkIndex.TriggerOperationsByConnector maps connector → valid trigger operations
• For typo detection, use simple Levenshtein distance; suggest the closest match if distance <= 2

Acceptance Criteria

• All 9 diagnostics implemented and tested
• Diagnostics appear as squiggles on the attribute argument value (precise range)
• Typo suggestion includes the correct value in the message
• Unit tests with mock SdkIndex covering valid, invalid, and typo scenarios