[KSemenenko]

Changes

• Bind report block content through its init property during JSON deserialization. Tool schema export can represent omitted content while report callers retain the existing block and content types.
• Exercise the public report method through Microsoft.Extensions.AI schema generation. Render a PDF with a content-free page break and a populated text block.
• Release the repair as FileContext 1.0.20.

Verification

• The new regression reproduced the schema-export exception before the fix.
• All 19 focused report tests and all 232 Release tests passed.
• Formatting, package audit, and Release packaging passed.