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>

lib/go/tests/parse.sx

@@ -111,6 +111,67 @@
       (ast-app (ast-var "|") (list (ast-var "a") (ast-var "b")))
       (ast-var "c"))))
 
+(go-parse-test
+  "unary: -a"
+  (go-parse "-a")
+  (ast-app (ast-var "-") (list (ast-var "a"))))
+
+(go-parse-test
+  "unary: +a"
+  (go-parse "+a")
+  (ast-app (ast-var "+") (list (ast-var "a"))))
+
+(go-parse-test
+  "unary: !x"
+  (go-parse "!x")
+  (ast-app (ast-var "!") (list (ast-var "x"))))
+
+(go-parse-test
+  "unary: ^x (bitwise NOT)"
+  (go-parse "^x")
+  (ast-app (ast-var "^") (list (ast-var "x"))))
+
+(go-parse-test
+  "unary: *p (pointer deref)"
+  (go-parse "*p")
+  (ast-app (ast-var "*") (list (ast-var "p"))))
+
+(go-parse-test
+  "unary: &v (address-of)"
+  (go-parse "&v")
+  (ast-app (ast-var "&") (list (ast-var "v"))))
+
+(go-parse-test
+  "unary: <-ch (channel recv)"
+  (go-parse "<-ch")
+  (ast-app (ast-var "<-") (list (ast-var "ch"))))
+
+(go-parse-test
+  "unary: -1 (on literal)"
+  (go-parse "-1")
+  (ast-app (ast-var "-") (list (ast-literal "1"))))
+
+(go-parse-test
+  "unary: !!x (chained, right-recursive)"
+  (go-parse "!!x")
+  (ast-app
+    (ast-var "!")
+    (list (ast-app (ast-var "!") (list (ast-var "x"))))))
+
+(go-parse-test
+  "unary: -a + b → ((-a) + b) — unary tighter than binary"
+  (go-parse "-a + b")
+  (ast-app
+    (ast-var "+")
+    (list (ast-app (ast-var "-") (list (ast-var "a"))) (ast-var "b"))))
+
+(go-parse-test
+  "unary: a + -b → unary applies to RHS"
+  (go-parse "a + -b")
+  (ast-app
+    (ast-var "+")
+    (list (ast-var "a") (ast-app (ast-var "-") (list (ast-var "b"))))))
+
 (go-parse-test "non-primary: '+'" (go-parse "+") nil)
 
 (go-parse-test "non-primary: empty" (go-parse "") nil)