feat: add the operations layer for declared plugin actions

src/backend/operations/registry.ts

@@ -0,0 +1,84 @@
+/**
+ * Handlers plugins registered for the actions their manifest declares.
+ *
+ * Same generation rule as service-registry.ts: a plugin that crashed and
+ * restarted must not have its old disposer remove the new registration, and a
+ * run that resolved a handler before a reload must not call the stale one.
+ */
+
+import type {
+  OperationAction,
+  OperationResult,
+} from "@termix-ssh/plugin-sdk/operations";
+
+export interface OperationRunContext {
+  hostId?: number;
+  resourceKey?: string;
+  runId: string | null;
+  dryRun: boolean;
+  signal: AbortSignal;
+  log: (line: string) => void;
+}
+
+export interface OperationHandler {
+  run: (
+    input: Record<string, unknown>,
+    context: OperationRunContext,
+  ) => Promise<OperationResult> | OperationResult;
+  /** What a dry run reports when the action has no native dry run. */
+  describe?: (
+    input: Record<string, unknown>,
+    context: OperationRunContext,
+  ) => string | Promise<string>;
+}
+
+export interface OperationRegistration {
+  pluginId: string;
+  action: OperationAction;
+  handler: OperationHandler;
+  generation: number;
+}
+
+const registrations = new Map<string, OperationRegistration>();
+let generationCounter = 0;
+
+export function registerAction(
+  pluginId: string,
+  action: OperationAction,
+  handler: OperationHandler,
+): OperationRegistration {
+  const existing = registrations.get(action.id);
+  if (existing && existing.pluginId !== pluginId) {
+    throw new Error(
+      `Action "${action.id}" is already registered by ${existing.pluginId}`,
+    );
+  }
+  const entry = {
+    pluginId,
+    action,
+    handler,
+    generation: ++generationCounter,
+  };
+  registrations.set(action.id, entry);
+  return entry;
+}
+
+/** Removes only the exact registration given. */
+export function revokeAction(registration: OperationRegistration): boolean {
+  const current = registrations.get(registration.action.id);
+  if (!current || current.generation !== registration.generation) return false;
+  return registrations.delete(registration.action.id);
+}
+
+export function getAction(id: string): OperationRegistration | undefined {
+  return registrations.get(id);
+}
+
+export function listActions(): OperationRegistration[] {
+  return [...registrations.values()];
+}
+
+/** Test seam. */
+export function clearOperationRegistry(): void {
+  registrations.clear();
+}