go: parse.sx — unary prefix operators + 11 tests [nothing]

Adds Go unary prefix operators per Go spec § Operators:
  +x  -x  !x  ^x  *p  &v  <-ch

gp-parse-unary is recursive (so !!x and -^x chain correctly) and
sits between gp-parse-expr and gp-parse-primary — unary therefore
always binds tighter than any binary op without needing a unary
entry in the precedence table.

Symbols +, -, *, &, ^ are shared between unary and binary forms;
the positional split (expression-start sees unary, mid-expression
sees binary) disambiguates them cleanly with no lookback.

Unary nodes are single-arg ast-app:
  (ast-app (ast-var OP) (list OPERAND))

parse 37/37, total 166/166.

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

plans/go-on-sx.md

@@ -160,7 +160,9 @@ Progress-log line → push `origin/loops/go`.
 - [x] Binary operators (Pratt precedence climbing using `pratt-op-lookup`
       + Go precedence table). Operator app emitted as
       `(ast-app (ast-var OP) [LHS RHS])`; left-assoc raises right-min by 1.
-- [ ] Unary operators (`!x`, `-x`, `^x`, `*p`, `&v`, `<-ch`).
+- [x] Unary operators (`+x`, `-x`, `!x`, `^x`, `*p`, `&v`, `<-ch`).
+      `gp-parse-unary` recursive, sits between `gp-parse-expr` and
+      `gp-parse-primary`; right-associative chains (`!!x`).
 - [ ] Function calls `f(a, b)` and member access `x.field`.
 - [ ] Index `x[i]` and slice `x[a:b]`/`x[a:b:c]`.
 - [ ] Type assertion `v.(T)`.
@@ -176,7 +178,7 @@ Progress-log line → push `origin/loops/go`.
       assign, short-decl `:=`, send `ch <- v`, recv `<-ch`.
 - [ ] End-to-end: hello-world, fibonacci, FizzBuzz, goroutine ping-pong,
       struct + method.
-- **Acceptance:** parse/ suite at 80+ tests. Current: 26/26.
+- **Acceptance:** parse/ suite at 80+ tests. Current: 37/37.
 
 ### Phase 3 — Bidirectional type checker, MVP (`lib/go/types.sx`) ⬜
 - **Independent implementation.** Do NOT use lib/guest/static-types-
@@ -435,6 +437,13 @@ 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 cont.: unary prefix operators (`+`, `-`, `!`, `^`,
+  `*`, `&`, `<-`). `gp-parse-unary` is recursive (`!!x`) and sits between
+  `gp-parse-expr` and `gp-parse-primary` so unary always binds tighter
+  than any binary. Symbols `+ - * & ^` are shared with binary; the
+  positional split (expression-start vs mid-expression) disambiguates
+  cleanly without lookback. Unary nodes are single-arg `ast-app`. +11
+  tests, parse 37/37, total 166/166. `[nothing]` — pure Go parser work.
 - 2026-05-27 — Phase 2 cont.: binary operators via Pratt precedence
   climbing. `gp-pratt-loop` consumes `pratt-op-lookup` against
   `go-precedence-table`; left-assoc bumps right-min by 1, right-assoc