refactor(tangle): isolate workspace metadata and recovery

.changeset/tangle-workspace-modules.md

@@ -0,0 +1,6 @@
+---
+"@tangle-network/agent-provider-tangle": patch
+---
+
+Separate workspace metadata encoding and durable recovery from operation handling.
+Reuse the canonical attestation codec and shared identifier validation without changing the public provider contract.

packages/agent-provider-tangle/package.json

@@ -95,6 +95,10 @@
     "dist/tangle-workspace-branching.js",
     "dist/tangle-confidential-attestation.d.ts",
     "dist/tangle-confidential-attestation.js",
+    "dist/tangle-workspace-markers.d.ts",
+    "dist/tangle-workspace-markers.js",
+    "dist/tangle-workspace-recovery.d.ts",
+    "dist/tangle-workspace-recovery.js",
     "README.md",
     "LICENSE"
   ],

packages/agent-provider-tangle/src/tangle-contract-safety.ts

@@ -17,15 +17,9 @@ const IMMUTABLE_TANGLE_IMAGE =
   /^(?:sha256:[a-f0-9]{64}|\S+@sha256:[a-f0-9]{64})$/i;
 
 export function boundedIdentifier(value: unknown, label: string): string {
-  if (
-    typeof value !== "string" ||
-    value.length === 0 ||
-    value.length > MAX_IDENTIFIER_LENGTH ||
-    value.trim() !== value
-  ) {
-    throw new Error(`${label} is invalid`);
-  }
-  return value;
+  const identifier = safeIdentifier(value);
+  if (identifier === undefined) throw new Error(`${label} is invalid`);
+  return identifier;
 }
 
 export function boundedString(value: unknown, label: string): string {
@@ -288,3 +282,29 @@ export async function awaitWithSignalAndCleanup<T>(
     if (listener) signal.removeEventListener("abort", listener);
   }
 }
+
+export function cloneJson<T>(value: T): T {
+  assertBoundedJson(value);
+  return structuredClone(value);
+}
+
+export function safeIdentifier(value: unknown): string | undefined {
+  if (
+    typeof value !== "string" ||
+    value.length === 0 ||
+    value.length > MAX_IDENTIFIER_LENGTH ||
+    value.trim() !== value
+  )
+    return undefined;
+  return value;
+}
+
+export function safeString(value: unknown): string | undefined {
+  if (
+    typeof value !== "string" ||
+    value.length === 0 ||
+    value.length > MAX_STRING_LENGTH
+  )
+    return undefined;
+  return value;
+}