A program importing two modules with the last segment 'parser' (jq's and jsonpath's) fails: 'free_query' is not exported from module 'parser' #3103

contrib/jq's test_after_jsonpath.ae (and test_with_jsonpath.ae) do not compile:

cd contrib/jq && aetherc --check test_after_jsonpath.ae
error[E0303]: 'free_query' is not exported from module 'parser'

ae build fails the same way (main at v0.839.0, and 639d264). The program imports two modules whose last path segment is parser (jq's own parser and jsonpath's), and a qualified parser.free_query resolves against the wrong one. #2255 made two shipped modules sharing a last segment a checked case, but a program that imports both still collides here.

Expected: each parser. call resolves to the module that import bound (its full path, or the alias the program gave), so both programs build and run; if two imports genuinely cannot be told apart, the error names both modules and how to alias one.

Also in contrib/jq, two W1002 unreachable-code warnings (eval.ae:3650, lexer.ae:144) to remove. Found on #3101.