Add --filter option to data schema command

[joshsmithxrm]

Problem

No CLI way to add filters during schema generation. Users must manually edit the generated XML and use the awkward HTML-encoded format:

<filter>&lt;filter type="and"&gt;&lt;condition attribute="country" operator="eq" value="US"/&gt;&lt;/filter&gt;</filter>

Proposed Solution

Add --filter option using SQL-like syntax (matches existing update/delete commands):

ppds data schema -e account,contact -o schema.xml \
  --filter "account:statecode eq 0" \
  --filter "contact:createdon gt 2024-01-01"

The filter expression uses the same syntax as ppds data update --filter and ppds data delete --filter, leveraging the existing SqlToFetchXmlTranspiler.

Implementation

File	Change
src/PPDS.Cli/Commands/Data/SchemaCommand.cs	Add --filter option (repeatable, format: entity:expression)
src/PPDS.Migration/Schema/SchemaGeneratorOptions.cs	Add EntityFilters dictionary property
src/PPDS.Migration/Schema/DataverseSchemaGenerator.cs	Apply filters to generated EntitySchema objects
tests/PPDS.LiveTests/Cli/DataSchemaCommandE2ETests.cs	Add filter tests

Validation

• Error if --filter "foo:..." but foo not in --entities list
• Validate filter syntax before writing schema

Related

• CmtSchemaReader doesn't support nested XML filter format #500 - CmtSchemaReader XML format bug (the HTML-encoded format workaround)
• Add filter feedback during data export #501 - Filter feedback during export