feat(analyzer): walk CLASS method bodies for undeclared-var warnings

Phase 2 of the analyzer originally only called analyzeFunc on
*ast.FuncDecl. Class methods parse as *ast.MethodDecl and were
silently skipped — meaning anything inside `METHOD Foo() CLASS TBar`
got zero static checking, including the undeclared-variable scan.

This is what let FindExclusive's DBI_FULLPATH / DBI_SHARED references
ship: the gengo fallback (now PushMemvar, previously PushLocal(0))
turned them into runtime NIL / crash, but the analyzer never flagged
them at build time because it never descended into the method body.

Fix: add analyzeMethod — same scope setup as analyzeFunc (module
statics, parameters, LOCAL/STATIC decls) — and route MethodDecl to
it from the Phase 2 dispatch.

Also register PCCOMPILE / PCEVAL / SQLSCAN in the RTL allow-list so
FiveSql2's new pcode hot-path RTL doesn't trip the warning.

Expected side effect: the FiveSql2 build now emits 17 real warnings
from TSqlIndex.prg — undefined DBOI_* order-info constants and
unregistered RTL functions (FieldType, FieldLen, ordCreate,
dbCreateIndex, dbClearIndex). These are real tech debt hiding behind
PushMemvar's silent NIL fallback; left as-is to surface them rather
than suppress.

Validation:
  - FiveSql2 43/43
  - Harbour compat 51/51
  - go test ./compiler/analyzer/... PASS

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

compiler/analyzer/analyzer.go

@@ -111,11 +111,13 @@ func Analyze(file *ast.File, externalFuncs ...map[string]bool) []Diagnostic {
 		}
 	}
 
-	// Phase 2: Analyze each function
+	// Phase 2: Analyze each function and class method body
 	for _, d := range file.Decls {
 		switch decl := d.(type) {
 		case *ast.FuncDecl:
 			a.analyzeFunc(decl)
+		case *ast.MethodDecl:
+			a.analyzeMethod(decl)
 		}
 	}
 
@@ -175,6 +177,63 @@ func (a *Analyzer) analyzeFunc(fn *ast.FuncDecl) {
 	}
 }
 
+// analyzeMethod walks a class-method body (`METHOD Foo() CLASS TBar`)
+// applying the same undeclared-variable and unused-variable checks
+// that analyzeFunc performs on standalone functions. Without this,
+// unresolved identifiers inside CLASS methods silently fell through
+// to gengo's memvar fallback (NIL at runtime) — e.g. a missing
+// `#include "dbinfo.ch"` leaving DBI_FULLPATH undefined in a method.
+func (a *Analyzer) analyzeMethod(m *ast.MethodDecl) {
+	a.scope = &Scope{
+		Name:     m.Name,
+		Declared: make(map[string]VarInfo),
+		Used:     make(map[string]bool),
+	}
+
+	// Module-level STATICs are visible to class methods too
+	for name, info := range a.moduleStatics {
+		a.scope.Declared[name] = info
+	}
+
+	// Parameters
+	for _, p := range m.Params {
+		a.scope.Declared[strings.ToUpper(p.Name)] = VarInfo{
+			Name:    p.Name,
+			Pos:     p.NamePos,
+			IsParam: true,
+		}
+	}
+
+	// LOCAL / STATIC declarations inside the method
+	for _, d := range m.Decls {
+		if vd, ok := d.(*ast.VarDecl); ok {
+			for _, v := range vd.Vars {
+				a.scope.Declared[strings.ToUpper(v.Name)] = VarInfo{
+					Name: v.Name,
+					Pos:  v.NamePos,
+					Kind: vd.Scope,
+				}
+			}
+		}
+	}
+
+	for _, stmt := range m.Body {
+		a.analyzeStmt(stmt)
+	}
+
+	// Unused-variable hints (same exclusions as analyzeFunc)
+	for name, info := range a.scope.Declared {
+		if !a.scope.Used[name] && !info.IsParam {
+			lower := strings.ToLower(info.Name)
+			if lower == "i" || lower == "j" || lower == "k" || lower == "n" ||
+				lower == "err" || lower == "_" {
+				continue
+			}
+			a.hint(info.Pos, "unused variable '%s'", info.Name)
+		}
+	}
+}
+
 func (a *Analyzer) analyzeStmt(stmt ast.Stmt) {
 	if stmt == nil {
 		return
@@ -487,6 +546,8 @@ var rtlFunctions = map[string]bool{
 	"DBRECALL": true, "DBCOMMIT": true, "DBRLOCK": true, "DBRUNLOCK": true,
 	"DBSEEK": true, "DBSELECTAREA": true, "DBPACK": true, "DBZAP": true,
 	"DBCREATE": true, "DBINFO": true, "DBORDERINFO": true, "DBSETINDEX": true,
+	// FiveSql2 hybrid hot-path RTL (pcode + Go-native scan)
+	"PCCOMPILE": true, "PCEVAL": true, "SQLSCAN": true,
 	"RECALL": true, "PACK": true, "ZAP": true,
 	"FLOCK": true, "DBUNLOCK": true,
 	"__DBPACK": true, "__DBZAP": true,