Shared-parser hook for NilPy str methods (filed for traceability)

Track N's [[feature-nilpy-str-methods]] needs one branch in the SHARED compiler/parser.inc, which is Track A/P ground — filed per the combined-track rule and self-resolved (the same session held A and N, with no other agent on A).

What was added

parser.inc gains exactly two things, both PyExprMode-gated so the Pascal dialect is untouched:

• a forward declaration of PyParseStrMethod (mirroring the existing PyParseListLiteral forward — pyparser.inc is included after parser.inc, so this is how the shared parser reaches N's code);
• a branch in the postfix .member path that, when the base is string-typed and the next token is (, delegates to PyParseStrMethod and feeds the call's return type back into the suffix loop so chains keep parsing.

All method-set knowledge lives in pyparser.inc and pylib.pas (Track N / Track B files). The shared parser only learns WHERE the form is legal, not what it means — so growing the method set never touches A's ground again.

Gate: test-nilpy GREEN, --tier quick GREEN, self-host fixedpoint byte-identical.