Add 6 new tests using real corpus fixtures (colours, MPD, TEXMAP, syntax, BFC, corpus-wide). Fix parser bugs they exposed: - Primitive colour token validation (keyword kinds 0-5 valid as colours) - TEXMAP numeric keyword handling and NEXT state - Model-local DATA payload state - MPD virtual file count 11/12 tests pass. 1 remaining: corpus-wide fixture outcome test has 1-2 adversarial fixture diagnostic mismatches. Epic: PM-86 Task: PM-78