plugin(telemetry-watcher): inline plugin SDK to break ESM TS chain

@fusion/plugin-sdk's package.json points its import entry at
src/index.ts (TS source), and that file imports core/src/plugin-types.js
via relative path. Node 22 ESM has no TS loader so the chain
unraveled at runtime: the plugin loader successfully resolved our
compiled dist/index.js, but the very first `import { definePlugin }
from "@fusion/plugin-sdk"` walked into TS source and fell over.

definePlugin is a pure typed identity function — it adds no runtime
behavior. Inline its source plus a structural copy of the plugin
context/route/manifest types we use, drop the @fusion/plugin-sdk
dependency entirely. The compiled output now imports nothing outside
node:crypto and Node builtins, so it can load anywhere fusion can
spawn ESM modules.

When fusion publishes a compiled SDK build, swap the inline types
back to import statements and restore the workspace dependency.

plugins/fusion-plugin-telemetry-watcher/src/index.ts

@@ -23,13 +23,73 @@
  */
 
 import { createHash } from "node:crypto";
-import { definePlugin } from "@fusion/plugin-sdk";
-import type {
-  FusionPlugin,
-  PluginContext,
-  PluginRouteDefinition,
-  PluginSettingSchema,
-} from "@fusion/plugin-sdk";
+
+// ── Inline plugin SDK surface ──────────────────────────────────────────────
+//
+// We deliberately do NOT import from "@fusion/plugin-sdk" at runtime. The
+// SDK package has its `import` export entry pointing at a TypeScript file
+// (src/index.ts) which itself imports more TS files from @fusion/core via
+// relative paths. Node 22 ESM cannot resolve those without a TS loader at
+// runtime, so the loader fails before our handler ever runs. The SDK
+// surface we actually use is structural: definePlugin is a typed identity
+// helper, and the type aliases are erased at compile time. Inlining these
+// lets the compiled dist/index.js load without traversing into TS sources.
+//
+// When fusion publishes a compiled SDK build, swap these back to import
+// statements and remove the local declarations.
+
+interface PluginSettingSchema {
+  type: "string" | "number" | "boolean" | "enum" | "password" | "array";
+  label?: string;
+  description?: string;
+  defaultValue?: unknown;
+  required?: boolean;
+  enumValues?: string[];
+  multiline?: boolean;
+  itemType?: "string" | "number";
+}
+
+interface PluginLogger {
+  info(message: string, ...args: unknown[]): void;
+  warn(message: string, ...args: unknown[]): void;
+  error(message: string, ...args: unknown[]): void;
+  debug(message: string, ...args: unknown[]): void;
+}
+
+interface PluginContext {
+  pluginId: string;
+  taskStore: unknown;
+  settings: Record<string, unknown>;
+  logger: PluginLogger;
+  emitEvent: (event: string, data: unknown) => void;
+}
+
+interface PluginRouteDefinition {
+  method: "GET" | "POST" | "PUT" | "DELETE";
+  path: string;
+  description?: string;
+  handler: (req: unknown, ctx: PluginContext) => Promise<unknown>;
+}
+
+interface FusionPlugin {
+  manifest: {
+    id: string;
+    name: string;
+    version: string;
+    description?: string;
+    settingsSchema?: Record<string, PluginSettingSchema>;
+  };
+  state: "installed" | "started" | "stopped" | "error";
+  hooks?: {
+    onLoad?: (ctx: PluginContext) => Promise<void> | void;
+    onUnload?: () => Promise<void> | void;
+  };
+  routes?: PluginRouteDefinition[];
+}
+
+function definePlugin(plugin: FusionPlugin): FusionPlugin {
+  return plugin;
+}
 
 // ── Severity classifier ─────────────────────────────────────────────────────
 
@@ -532,7 +592,11 @@ const plugin: FusionPlugin = definePlugin({
           );
 
           try {
-            const task = await ctx.taskStore.createTask({
+            const taskStore = ctx.taskStore as {
+              createTask: (input: Record<string, unknown>) => Promise<{ id: string }>;
+              updateTask?: (id: string, patch: Record<string, unknown>) => Promise<unknown>;
+            };
+            const task = await taskStore.createTask({
               title: `[${severity}] ${item.alertname}`,
               description,
               column: "triage",
@@ -545,20 +609,15 @@ const plugin: FusionPlugin = definePlugin({
               } as never,
             });
 
-            if (triageAgentId) {
-              const store = ctx.taskStore as unknown as {
-                updateTask?: (id: string, patch: Record<string, unknown>) => Promise<unknown>;
-              };
-              if (typeof store.updateTask === "function") {
-                try {
-                  await store.updateTask(task.id, { assignedAgentId: triageAgentId });
-                } catch (assignErr) {
-                  ctx.logger.warn(
-                    `Could not auto-assign task ${task.id}: ${
-                      assignErr instanceof Error ? assignErr.message : String(assignErr)
-                    }`,
-                  );
-                }
+            if (triageAgentId && typeof taskStore.updateTask === "function") {
+              try {
+                await taskStore.updateTask(task.id, { assignedAgentId: triageAgentId });
+              } catch (assignErr) {
+                ctx.logger.warn(
+                  `Could not auto-assign task ${task.id}: ${
+                    assignErr instanceof Error ? assignErr.message : String(assignErr)
+                  }`,
+                );
               }
             }