Adds generate/comprehension/lexeme_primitives.py with the eight seed
primitives specified by ADR-0164.1:
decimal-currency-literal (priority 10)
currency-literal (priority 20)
percentage-literal (priority 30)
fraction-literal (priority 40)
time-amount-literal (priority 50)
ordinal-literal (priority 60)
mass-noun-token (priority 70)
numeric-literal (priority 100)
LexemePrimitive and LexemeMatch are frozen/slots dataclasses. scan()
runs primitives in priority order and returns the first hit wrapped in
a MappingProxyType over sorted-key extracted_values for canonical-bytes
stability. All patterns use explicit space characters ([ ]?, [- ]?) not
\s so the ADR-0165 compliance invariant holds.
55 tests cover: construction invariants, canonical fires (each
primitive on its own example), overlap precedence ($18.00, 1/2, 50%),
refusal on Tina/empty/verbs, determinism, sorted-key stability, and
the ADR-0165 compliance smoke test.
