Mock provider: missing ':' or '=>' in an op declaration cascades into the next line #73

Audit finding M6 — verified live.

Problem

parse.rs parse_op calls expect_punct for : and => without checking the return. An op missing : produces the expected diagnostic but parsing keeps consuming: a second misattributed error appears, the next line's valid op is silently dropped, and the solution then reports a bogus unresolved-op. One syntax slip -> ~3 diagnostics + a lost declaration.

Reproduction

lpp/check on "puzzle p {\n target = 1\n start = 0\n ops {\n b x => x + 1\n c: x => x + 2\n }\n solution = [ b, c ]\n}"

Acceptance criteria

• A malformed op line is reported once, recovery resynchronizes at the line boundary, and the following op declaration still parses.
• Regression test + green suite.