diagcat.inc is the single catalog: one line per diagnostic with a stable
number in a per-category range. Included by errors.inc it gives E_*
constants; included by diagnostics.s it gives the message table.
docs/diagnostics.md is generated from it. The build rejects out-of-range
or duplicate numbers and any grammar .expect symbol missing from it.

diagnostics.s prints a two-line, 40-column-safe screen form and appends
full lines to NAME.ERR. NAME.ERR is scratched at the start and created
only when needed. After 20 errors, E221 replaces the next one and the
caller must stop. diskio.s gains output-file and DOS-command wrappers.

Verified in x128: screen RAM rows, diag.err and limit.err read back from
the D81, stale-file scratching, an unwritable ERR name (DOS 33 -> E201
once), and no open files after any phase. A counting mutation is caught.

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

src_load reads a SEQ file from device 8 once into a bank-1 cache (D118).
It enforces the 80-byte line, 599-line, and 18,999-byte limits as bytes
arrive and reports stable codes with exact positions. src_rewind and
src_next_line replay the cache one logical line at a time for every pass.
diskio.s wraps the KERNAL file calls; channels close on every path.

Verified in x128 with a 1581: eight fixtures, including the exact limits,
each limit error, a missing file (DOS 62), and a missing final $0D, all
match host-computed line counts, Fletcher-16 checksums, and positions.
Adds a shared PowerShell test library for x128 scripts.

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

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>