Make function property values camelCase

[SteveL-MSFT]

PR Summary

Function Category and ArgKind should be camelCase

PR Context

Fix #1582

[Copilot]

Pull request overview

This PR addresses issue #1582 by changing how function metadata enum values are serialized so that dsc function list (and related schema generation) emits camelCase string values instead of PascalCase.

Changes:

• Serialize FunctionArgKind enum variants using camelCase (e.g., String → string, Null → null).
• Serialize FunctionCategory enum variants using camelCase (e.g., System → system).
• Add a Pester test intended to validate camelCase naming in generated schemas (needs adjustment to allow reserved _camelCase fields).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
lib/dsc-lib/src/functions/mod.rs	Applies serde(rename_all = "camelCase") to function metadata enums so CLI output/schema enum values become camelCase.
dsc/tests/dsc_schema.tests.ps1	Adds a schema-wide camelCase validation test (currently too strict for underscore-prefixed reserved fields; should be relaxed).

Comments suppressed due to low confidence (1)

lib/dsc-lib/src/functions/mod.rs:111

• These enums now serialize their variants as camelCase (e.g. Resource -> resource, String -> string). That will break existing Pester expectations that currently assert PascalCase values for dsc function list output (e.g. dsc/tests/dsc_function_list.tests.ps1:18-22) and MCP list_dsc_functions expectations (e.g. dsc/tests/dsc_server.tests.ps1:259-261). Please update those tests (and any other consumers) to match the new serialized values so CI doesn’t fail.

/// The kind of argument that a function accepts.
#[derive(Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Serialize, JsonSchema, DscRepoSchema)]
#[dsc_repo_schema(base_name = "argKind", folder_path = "definitions/functions/builtin")]
#[serde(rename_all = "camelCase")]
pub enum FunctionArgKind {
    Array,
    Boolean,
    Lambda,
    Null,
    Number,
    Object,
    String,