go: parse.sx — multi-form file parsing + 7 e2e tests; PHASE 2 COMPLETE [nothing]

Final Phase 2 sub-deliverable. go-parse now handles whole Go files:

  - Empty source → nil
  - Single top-level form → that form (backward-compatible with ~169
    existing single-stmt / single-decl tests)
  - Multiple forms → (list :file FORMS), the canonical Go file shape

Implementation: gp-parse-all loops gp-parse-top until eof, tolerating
ASI semis between forms, then returns based on form count.

End-to-end test set (asserts the top-level decl-tag sequence via a
new decl-tags helper, not the full AST tree — that'd be unwieldy):

  - hello-world             :package :import :func-decl
  - recursive fibonacci     :package :func-decl
  - FizzBuzz                :package :import :func-decl
  - goroutine ping-pong     :package :func-decl :func-decl
  - struct + method         :package :type-decl :method-decl :func-decl
  - interface + method      :package :type-decl :type-decl :method-decl
  - defer + select + range  :package :func-decl

Type-switch (`switch v := x.(type) { ... }`) is the one syntactic
shape still deferred from Phase 2; doesn't gate Phase 3.

**Phase 2 (parser) is complete.** parse 176/176, total 305/305. Next:
Phase 3 — bidirectional type checker. The sister-plan diary for
static-types-bidirectional already has the :field binding-group
insight; Phase 3 will add the synth/check shape that emerges.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plans/go-on-sx.md

@@ -153,7 +153,7 @@ Progress-log line → push `origin/loops/go`.
 - **Acceptance:** lex/ suite at 50+ tests. Current: 129/129. **Phase 1
   done** — hex floats deferred (rare). Move to Phase 2 next.
 
-### Phase 2 — Parser (`lib/go/parse.sx`) ⬜
+### Phase 2 — Parser (`lib/go/parse.sx`) ✅
 - [x] Parser scaffold + Go operator-precedence table (entry shape from
       `lib/guest/pratt.sx`) + primary expressions (int/float/imag/string/
       rune/ident → ast-literal / ast-var via `lib/guest/ast.sx`).
@@ -203,11 +203,15 @@ Progress-log line → push `origin/loops/go`.
       bare-recv / default)** all done. Composite-literal `{` suppression
       active in control-flow conditions. Type-switch (`switch v :=
       x.(type)`) deferred to a follow-up.
-- [ ] End-to-end: hello-world, fibonacci, FizzBuzz, goroutine ping-pong,
-      struct + method.
-- **Acceptance:** parse/ suite at 80+ tests. **Acceptance bar crossed:
-  169/169.** Remaining sub-item (end-to-end programs) keeps Phase 2
-  open ⬜.
+- [x] End-to-end: hello-world, fibonacci, FizzBuzz, goroutine ping-pong,
+      struct + method, interface, defer+select+range. `go-parse` extended
+      to handle multi-form files: returns the single form for one-form
+      input (backward compat) or `(list :file FORMS)` for multiple.
+      Structural tests assert top-level decl-tag sequences via the
+      `decl-tags` helper rather than full ASTs.
+- **Acceptance:** parse/ suite at 80+ tests. Current: **176/176**.
+  **Phase 2 complete.** Type-switch is the one syntactic shape still
+  deferred to a follow-up; it doesn't gate Phase 3.
 
 ### Phase 3 — Bidirectional type checker, MVP (`lib/go/types.sx`) ⬜
 - **Independent implementation.** Do NOT use lib/guest/static-types-
@@ -524,6 +528,16 @@ Minimal repro: see `lib/go/lex.sx#gl-oct-digit?` and `#gl-match-op`.
 
 _Newest first. Append one dated entry per commit._
 
+- 2026-05-27 — **Phase 2 complete.** End-to-end multi-form file parsing.
+  `go-parse` now returns single forms for backward compat (~169 tests
+  unchanged) or `(list :file FORMS)` for multi-form input. Tests cover
+  hello-world, fibonacci, FizzBuzz, goroutine ping-pong, struct+method,
+  interface+method, and defer+select+range — each asserted via top-
+  level `decl-tags`. Type-switch is the one syntactic shape still
+  deferred. +7 tests, parse 176/176, total 305/305. Next: Phase 3
+  (bidirectional type checker). `[nothing]` — pure Go parser
+  composition; the cross-language insights are already in the sister-
+  plan diaries from earlier Phase 2 commits.
 - 2026-05-27 — Phase 2 cont.: `switch` and `select` statements.
   Tagged + tagless switch, multi-value cases, `default`, and select
   with recv-into-var / send / bare-recv / default cases. New