[simonbs]

Adds Nix and XML parser, query-resource, and Runestone wrapper products. Neither overlaps the ten languages in #34. App integration is in simonbs/RunestoneEditor#12.

Nix highlighting now preserves function and property styling when themes also color ordinary variables. XML queries adapt entity predicates and markup captures to Runestone. LANGUAGE_SOURCES.md records exact source pins, licenses, adaptations, audit evidence, and limitations.

The quality audit removed Clojure, Fortran, Kotlin, Org, and PowerShell: incomplete core highlighting, ordinary fixed-form Fortran failures, hidden missing-semicolon errors in valid Kotlin interfaces, missing Org inline semantics, and PowerShell range/attribute parsing defects. Their products, sources, and notices are absent from the final diff; detailed examples are recorded in LANGUAGE_SOURCES.md.

Validation:

• Nix: 45 valid corpus tree checks and nine expected-error cases; four real upstream files.
• XML: ten valid corpus tree checks and six expected-error cases; 17 real app XML files.
• Four persistent fixtures pass on Tree-sitter 0.20.9 and 0.27.1, asserting 46 positive and five excluded captures. The existing compatibility CI runner executes these fixtures.
• Native iOS tests pass for Nix capture precedence and XML entity/Unicode highlighting, using Runestone's actual Swift predicates and attributed-string highlighter. These tests are local-only; CI currently builds the package and runs the C/Python compatibility checks.
• Native compilation/testing used the existing build-only iOS 16 deployment override for Runestone 0.4.1's availability issue with the installed SDK. Package deployment requirements are unchanged.

Known limits: Nix builtin shadowing has no scope analysis. Compact internal XML DTD declarations without separating whitespace produce missing-whitespace nodes, but tested downstream highlighting recovers. No full conformance, incremental-edit, or UI appearance guarantee is claimed.