[Milestone A] A-01: Fix whitespace text node suppression in AspxParser #76
Description
Milestone A — Parser Hardening (A-01)
Priority: P0 — Foundation
Size: Small
Branch: experiment/aspx-middleware
File: src/BlazorWebFormsComponents.AspxMiddleware/AspxParser.cs (~line 177)
Problem
The AspxParser silently drops whitespace-only text nodes via an IsNullOrWhiteSpace check. This breaks layout and spacing in rendered pages — whitespace between inline controls (e.g., <asp:Label>\ followed by <asp:TextBox>) is layout-significant in HTML.
Acceptance Criteria
- Remove or narrow the \IsNullOrWhiteSpace\ check so whitespace-only nodes are preserved as \AspxTextNode\ instances
- Preserve \n, \r\n, single spaces, and runs of spaces
- Only discard truly empty nodes ("")
- All ~52 existing tests still pass
Context
See: \dev-docs/milestones/ASPX-MIDDLEWARE-MILESTONES.md\ § Milestone A
See: \dev-docs/aspx-middleware-migration-landscape.md\ §4.1