Add cfg/compiler.cfg, the production mmu.s, c128.inc, and the test mailbox,
proven by a capacity-checking skeleton in x128:

- 8K bottom common RAM, shared code at $1300, private zero page at bank 0
  page $1A via P0, bank-1 tables at $2000-$BFFF, test mailbox at $1BF0
- ld65 rejects overflows of the ZP, COMMON, MAIN, SWSTACK, and TABLES areas
- a CIA #2 timer NMI taken under bank 1 with the private zero page returns
  cleanly through the NMI guard (closes the E01-S03 NMI risk)
- decision D117 records the map; RESTORE is ignored while compiling

Also pin newLang/ to LF in .gitattributes. A branch switch under
core.autocrlf had rewritten the byte-exact fixtures with CRLF.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Nova128 is an object-oriented language with an on-machine C128 compiler.
This adds the spec, decisions, architecture, backlog, and story claims,
plus the grammar fixtures (E00-S02), disk-image builder (E07-S01), and
the x128-verified platform probes:

- E01-S01 minimal native PRG
- E01-S02 MMU/common-RAM probe. With bottom common on, a P0/P1 pointer
  aimed at bank 1 lands in bank 0 at the translated page. The verifier
  traces every MMU write in the probe window.
- E01-S03 KERNAL wrapper (kcall). CHROUT, drive status, and a
  device-not-present failure work from bank 0 and bank 1 mappings.
  A/X/Y/C/ST are preserved and the MMU state is restored exactly.
- E01-S04 40/80-column display and clock probe

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>