0fb6af9354
Adding `paths` to the global PRIMARY_ARG_KEYS hid the pattern for the
structural tools: ast_grep ({pat,paths}) and ast_edit ({ops,paths})
rendered scope-only (e.g. `ast_grep(src/**/*.ts)`), dropping `pat`/`ops`
— the most decision-relevant argument. Drop the global `paths` key and
special-case `find` (mirroring `search`) so find/search still surface
scope while ast_grep/ast_edit keep showing their pattern via the
existing fallback. Adds regression tests for both structural tools.