feat: add TLS for node bridge

apps/ios/Sources/Bridge/BridgeTLS.swift

@@ -0,0 +1,67 @@
+import CryptoKit
+import Foundation
+import Network
+import Security
+
+struct BridgeTLSParams: Sendable {
+    let required: Bool
+    let expectedFingerprint: String?
+    let allowTOFU: Bool
+    let storeKey: String?
+}
+
+enum BridgeTLSStore {
+    private static let service = "com.clawdbot.bridge.tls"
+
+    static func loadFingerprint(stableID: String) -> String? {
+        KeychainStore.loadString(service: service, account: stableID)?.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    static func saveFingerprint(_ value: String, stableID: String) {
+        _ = KeychainStore.saveString(value, service: service, account: stableID)
+    }
+}
+
+func makeBridgeTLSOptions(_ params: BridgeTLSParams?) -> NWProtocolTLS.Options? {
+    guard let params else { return nil }
+    let options = NWProtocolTLS.Options()
+    let expected = params.expectedFingerprint.map(normalizeBridgeFingerprint)
+    let allowTOFU = params.allowTOFU
+    let storeKey = params.storeKey
+
+    sec_protocol_options_set_verify_block(
+        options.securityProtocolOptions,
+        { _, trust, complete in
+            guard let trust else {
+                complete(false)
+                return
+            }
+            if let cert = SecTrustGetCertificateAtIndex(trust, 0) {
+                let data = SecCertificateCopyData(cert) as Data
+                let fingerprint = sha256Hex(data)
+                if let expected {
+                    complete(fingerprint == expected)
+                    return
+                }
+                if allowTOFU {
+                    if let storeKey { BridgeTLSStore.saveFingerprint(fingerprint, stableID: storeKey) }
+                    complete(true)
+                    return
+                }
+            }
+            let ok = SecTrustEvaluateWithError(trust, nil)
+            complete(ok)
+        },
+        DispatchQueue(label: "com.clawdbot.bridge.tls.verify"))
+
+    return options
+}
+
+private func sha256Hex(_ data: Data) -> String {
+    let digest = SHA256.hash(data: data)
+    return digest.map { String(format: "%02x", $0) }.joined()
+}
+
+private func normalizeBridgeFingerprint(_ raw: String) -> String {
+    raw.lowercased().filter { $0.isHexDigit }
+}