fix(pp): #xcommand/#xtranslate patterns with paren-attached keyword

Real Harbour headers write parameterised commands with no space
between the keyword and its opening paren:

  #xcommand MAKE_TEST( <obj>, <v> ) => ...

ParseRule stored the rule keyword as `MAKE_TEST(` (stripping only
<>, [] marker wrappers), but firstToken normalised source lines by
stopping the first-word scan at `(` — so `MAKE_TEST( o, 42 )`
produced `MAKE_TEST` for the lookup. The two strings didn't match
and the fast-path keyword check rejected every invocation, leaving
the macro unexpanded and the call site as a bare undeclared
identifier.

Trim everything from the first `(` onward during keyword
extraction so both halves agree on the dispatch key. The marker
tokens inside the parens are still parsed normally by
parseMarkers / matchPattern.

Verified with /tmp/test_xcmd2.prg (`MAKE_TEST( o, 99 )` expands
and dispatches to the object's :hVar access). FiveSql2 43/43,
Harbour compat 56/56, Go test ALL PASS.

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

compiler/pp/command.go

@@ -81,13 +81,19 @@ func ParseRule(directive string, isCommand, caseSens bool) *Rule {
 		ResultTmpl: result,
 	}
 
-	// Extract first keyword for fast matching
+	// Extract first keyword for fast matching. The first whitespace-
+	// delimited token of the pattern becomes the dispatch key; we
+	// strip marker wrappers and any trailing `(` so a pattern like
+	// `MAKE_TEST( <obj>, <v> )` hashes on `MAKE_TEST`, matching how
+	// firstToken normalises source lines.
 	words := strings.Fields(pattern)
 	if len(words) > 0 {
 		kw := words[0]
-		// Remove marker brackets
 		kw = strings.TrimLeft(kw, "<[")
 		kw = strings.TrimRight(kw, ">]")
+		if idx := strings.IndexByte(kw, '('); idx >= 0 {
+			kw = kw[:idx]
+		}
 		if !strings.ContainsAny(kw, "!*,:") {
 			rule.Keyword = kw
 		}