feat(web): visual rule builder with geo, CIDR and wildcard pickers

The rule editor no longer requires writing expr by hand. Conditions are rows of
field + operator + values joined with AND or OR, each row negatable, and the
generated expression is shown live and validated by the engine before a rule is
accepted. Raw expression and YAML editing are still available.

Fields cover the connection (protocol, source/destination IP and port), domains
(TLS SNI, QUIC SNI, DNS query name), HTTP (host, path, method, User-Agent) and
protocol detection. Operators cover CIDR membership, GeoIP countries, GeoSite
categories, port ranges, wildcards, substrings and regular expressions.
Multiple values in a row are OR-ed, so one row holds a whole domain or country
list.

Wildcards compile to the cheapest expression that matches them: *.x.com
becomes endsWith, x.* startsWith, *ad* contains, and only a star in the
middle falls back to a regular expression. Values are validated as they are
typed, including a hint when a star is used with an operator that would match
it literally.

Country and category pickers are backed by the databases the engine actually
loaded, via a new GET /api/v1/geo endpoint (cached, loaded on demand) built on
new listing methods in the geo package. Country names and flags come from
Intl.DisplayNames, so no name table is shipped. Note that the v2geo format has
no AS numbers; the provider groups it does contain (cloudflare, google,
telegram, ...) are listed alongside the countries.

Opening an existing rule parses its expression back into conditions. Anything
the builder cannot represent opens in the expression editor with a warning
rather than being rewritten. ruleset/expr_test.go pins the canonical
expressions the builder generates and compiles them with the real engine, and
the devserver now uses the real ruleset compiler so the same errors show up
during frontend work.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ruleset/expr_test.go

@@ -0,0 +1,76 @@
+package ruleset
+
+import (
+	"context"
+	"net"
+	"strings"
+	"testing"
+
+	"github.com/apernet/OpenGFW/analyzer"
+	"github.com/apernet/OpenGFW/analyzer/tcp"
+	"github.com/apernet/OpenGFW/analyzer/udp"
+	"github.com/apernet/OpenGFW/modifier"
+	modUDP "github.com/apernet/OpenGFW/modifier/udp"
+)
+
+// builderExpressions are the canonical expressions produced by the visual rule
+// builder of the web UI (see web/frontend/src/lib/rule/compile.ts). They are
+// pinned here so that a change to the expression language, the analyzers or the
+// built-in functions cannot silently break the builder.
+var builderExpressions = []string{
+	// Domain or subdomain, single and multiple values
+	`(string(tls?.req?.sni) == "example.com" || string(tls?.req?.sni) endsWith ".example.com")`,
+	`((string(tls?.req?.sni) == "example.com" || string(tls?.req?.sni) endsWith ".example.com") || (string(tls?.req?.sni) == "evil.test" || string(tls?.req?.sni) endsWith ".evil.test")) && proto == "tcp"`,
+	// CIDR and GeoIP, including negation
+	`(cidr(ip.dst, "10.0.0.0/8") || cidr(ip.dst, "fd00::/8")) || !(geoip(ip.dst, "cn") || geoip(ip.dst, "hk"))`,
+	// Port equality and ranges
+	`(port.dst >= 1000 && port.dst <= 2000) && (port.src == 80 || port.src == 443)`,
+	// Wildcards over DNS questions
+	`any(dns?.questions ?? [], {(string(.name) endsWith ".ads.com" || string(.name) startsWith "x.")})`,
+	// GeoSite over DNS questions
+	`any(dns?.questions ?? [], {geosite(string(.name), "category-ads-all")})`,
+	// HTTP fields: negation, regular expressions and header lookups
+	`!(string(http?.req?.headers?.host) contains "tracker") && string(http?.req?.path) matches "^/api/v\\d+/" && string(get(http?.req?.headers, "user-agent")) startsWith "curl"`,
+	// Protocol detection
+	`(ssh != nil || trojan != nil)`,
+	// Wildcard edge cases: "any value" and a star in the middle
+	`string(quic?.req?.sni) != "" && string(tls?.req?.sni) matches "^www\\..*\\.com$" && ip.src == "1.2.3.4" && string(http?.req?.method) == "POST"`,
+}
+
+func TestCompileBuilderExpressions(t *testing.T) {
+	analyzers := []analyzer.Analyzer{
+		&tcp.FETAnalyzer{}, &tcp.HTTPAnalyzer{}, &tcp.SocksAnalyzer{}, &tcp.SSHAnalyzer{},
+		&tcp.TLSAnalyzer{}, &tcp.TrojanAnalyzer{}, &udp.DNSAnalyzer{}, &udp.OpenVPNAnalyzer{},
+		&udp.QUICAnalyzer{}, &udp.WireGuardAnalyzer{},
+	}
+	modifiers := []modifier.Modifier{&modUDP.DNSModifier{}}
+	config := &BuiltinConfig{
+		Logger: nopLogger{},
+		// Point at a file that does not exist: expressions still have to
+		// compile, only loading the database is expected to fail.
+		GeoSiteFilename: "testdata/missing-geosite.dat",
+		GeoIpFilename:   "testdata/missing-geoip.dat",
+		ProtectedDialContext: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return (&net.Dialer{}).DialContext(ctx, network, address)
+		},
+	}
+
+	for _, expr := range builderExpressions {
+		rules := []ExprRule{{Name: "test", Action: "block", Expr: expr}}
+		_, err := CompileExprRules(rules, analyzers, modifiers, config)
+		if err == nil {
+			continue
+		}
+		// geoip()/geosite() need a database, which this test does not ship.
+		// Reaching the initialization step means the expression itself is fine.
+		if strings.Contains(err.Error(), "failed to initialize function") {
+			continue
+		}
+		t.Errorf("expression failed to compile: %s\n  %v", expr, err)
+	}
+}
+
+type nopLogger struct{}
+
+func (nopLogger) Log(StreamInfo, string)               {}
+func (nopLogger) MatchError(StreamInfo, string, error) {}