Implement workspace evolution, migrations, and runtime continuity

Enable evolution by default for source-backed workspaces. Add stable
conformance ownership, semantic-major review, candidate typechecking,
and durable fenced cutover with explicit migrations and forward recovery.

Independently supervise package runtimes so unchanged resource owners keep
their processes and connections across cutover. Add scoped invocation
authority, resource sessions, and typed callback rebinding.

Wire opaque object references through generated bindings and RPCs. Add
canonical relationship sets, keyed maps, and ordered lists with scoped
transactional mutations, revision checks, and inverse consistency. Support
planned cascade deletion, protection, tombstones, and lifecycle foundations.

Add journaled structural edits, package/function/migration scaffolding,
managed repository creation, and resumable bottom-up dependency pin
publication. Document lifetime boundaries, revision pinning, prototype
compatibility policy, commands, and deferred work.

Validate with 210 tests, user-systemd process/connection continuity,
generated-package TypeScript checks, and Nix host/protocol checks.
TTL handoff, physical reclamation, general multi-step migrations, and
root-systemd migration isolation acceptance remain deferred.

src/invocations.ts

@@ -0,0 +1,24 @@
+/** Execution completion, not HTTP disconnection, is the drain boundary. */
+export const createInvocationRegistry = () => {
+  const entries = new Map<string, { state: string; controller: AbortController }>();
+  return {
+    begin(id: string) {
+      if (!id || entries.has(id)) throw new Error("Invocation ID is missing or already used; invocations are never replayed implicitly");
+      // Completed identities remain until process retirement. A bounded process
+      // may reject new work; it must not evict and accidentally replay a call.
+      if (entries.size >= 100_000) throw new Error("Invocation registry full; explicit runtime retirement required");
+      const entry = { state: "running", controller: new AbortController() };
+      entries.set(id, entry);
+      return { signal: entry.controller.signal, finish(failed = false) { entry.state = failed ? "failed" : "completed"; } };
+    },
+    status(id: string) { return { invocationId: id, state: entries.get(id)?.state ?? "unknown" }; },
+    cancel(id: string) {
+      const entry = entries.get(id);
+      if (entry && ["running", "cancellation-requested"].includes(entry.state)) {
+        entry.state = "cancellation-requested";
+        entry.controller.abort();
+      }
+      return this.status(id);
+    },
+  };
+};