chore(license): align Cargo.toml license field to LICENSE (MPL-2.0) (#35)

Closes #34. Fixes manifest-vs-LICENSE inconsistency.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

Cargo.toml

@@ -3,7 +3,7 @@ name = "conflow"
 version = "0.1.0"
 edition = "2021"
 authors = ["Jonathan D.A. Jewell"]
-license = "MIT OR Apache-2.0"
+license = "MPL-2.0"
 description = "Configuration flow orchestrator for CUE, Nickel, and config validation workflows"
 repository = "https://gitlab.com/rhodium-standard/conflow"
 readme = "README.md"