G1b: extend qualified projection parse+resolve to pattern, fn type-annotation, and let/data type-annotation positions (gentle-gull execution receipt: #6641 only type-alias RHS; match-arm Closed => FatArrow/Dot; blocks Wave-0 (c))

[briansrls]

Summary

Extends Grammar lane G1 (#6641, which only wired qualified projection through type-alias RHS) to the remaining positions needed for Wave-0 (c) homonym qualification:

• v1 parse: parse_dotted_ident in match patterns (is_variant_pattern_start); typed let x: Type = expr with qualified type annotations
• v2 grammar: constructor_pattern uses qualified_name (match-arm closed by =>, dots in QN spines); let_expr gains optional : type_expr
• v1 resolve: lookup_variant_in_type routes dotted variant names through symbol_index_lookup (fail-closed on miss)
• Witness: import-less qualified_module_projection_g1b_fixture (fn return type, data annotation, let annotation) + enrollment claim

Fn/data type annotations already flowed through parse_type_expr from G1; G1b completes pattern + let and aligns v2 formal grammar.

Test plan

• ./target/release/regen_stage0 — wrote 95 generated stage0 files
• cargo build -p v1-compiler — green
• cargo run -p v1-compiler --bin v1_src_dag_parse — 39 files parse-clean
• gunbc compile --source-root dag --source-root src/v2 --target dag — green (full dag tree)

[gunbai-bot]

Review feedback (claude + cursor APPROVE): Verified — no code changes required from either review.

CI fix (b3ec352, synced to this branch): Same Unit→Int literal fix for the import-less g1b fixture; qualified type annotations unchanged.

— sent from neat-newt-628

[gunbai-bot]

Superseded by #6661. Canonical branch session/neat-newt-628 at a8cfbbe2 carries infer/resolve fixes, pattern fixture + qualified_module_projection_g1b_pattern_resolve_test.dag witnesses, and stage0 regen. This duplicate (session/neat-newt-628-g1b) is closed to avoid split maintenance.

— sent from neat-newt-628