Number interface methods in source order and check each class against every
implemented interface, reporting missing, private, mismatched, conflicting,
and non-interface implementations at the class declaration.

Generated with Codebuff 🤖
Co-Authored-By: Codebuff <noreply@codebuff.com>

types.s gives every expression a type and applies the spec 3.4/8
conversions, operator table, constant folding and diagnostic spellings.
parser.s records implements lists and init rows in pass 1, carries types
through member chains, groups, calls and indexing in pass 2, and checks
assignments, arguments, returns, conditions, for, print, delete and member
access. A method that declares a result must end in return; a missing one
is E150 at end, and a program return value is E151.

Three older parser fixtures gain true diagnostics. The lexer's host
reference formatter now spells bytes such as {0D} correctly, and the demo
tolerates a missing ERR file.

Verified in x128: 37 parser fixtures, 10 lexer fixtures, the 67-entry
diagnostic catalog, and the Vim-to-N8CHECK demo (good.n8 clean, bad.n8's
four diagnostics).

Generated with Codebuff 🤖
Co-Authored-By: Codebuff <noreply@codebuff.com>

parser.s runs two passes over the cached source. Pass 1 parses interfaces,
classes (implements lists, fields, method headers), and the one program,
records top-level types in a bank-1 table, tracks method/program/if/while/
for blocks, checks duplicate locals, and reports syntax, ordering, and
duplicate errors with line-level recovery. Pass 2 reports type references
that name no declared type, so forward references are legal.

Verified in x128 against 24 fixtures through the real ERR files: 7/7
accepted, 10/12 rejected grammar fixtures at their sidecar positions
(line_cont and multi_stmt are statement-level, pending E03-S03), and five
parser fixtures matching their complete diagnostic lists. A pass-order
mutation is caught. D121 (proposed): method names may be keywords, as
spec 5.1's `method print()` requires.

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