perf(dashnote): defer SDK value imports in note + contract helpers (#77)

* perf(dashnote): defer SDK value imports in note + contract helpers

NotesWorkspace, SessionContext, and LoginModal statically imported
contract.ts, createNote.ts, and updateNote.ts, each of which pulled
Document/DataContract/Identifier from @dashevo/evo-sdk. That anchored
the 8 MB SDK chunk to the entry graph via a hoisted static import, so
the browser fetched it before first paint despite the modulePreload
filter in vite.config.ts. Move the value imports behind a lazy module
cache (matching the loginWithPrivateKey pattern in 2b2c5a0) so the
chunk loads only when an authenticated write actually needs it.

Throttled Lighthouse (Slow 4G + 4× CPU, simulated mobile):
  LCP 30.8 s → 2.0 s, FCP 16.1 s → 1.7 s, perf score 0.55 → 0.98.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* refactor(dashnote): extract shared SDK lazy-loader to src/dash/sdkModule

Pull the duplicated `loadSdkModule` helper (type alias + cached promise +
loader function with retry-on-failure) out of contract.ts, createNote.ts,
and updateNote.ts into a single src/dash/sdkModule.ts, and have each
consumer import it. No behavior change — ESM module-graph caching makes
the previous three private promises functionally equivalent to one shared
promise. Tutorial files now show only their Dash SDK recipe without the
bundler-deferral plumbing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: thephez

example-apps/dashnote/src/dash/contract.ts

@@ -5,9 +5,8 @@
  *   sdk.contracts.publish({ dataContract, identityKey, signer })
  *   sdk.identities.nonce(identityId)
  */
-import { DataContract, Identifier } from "@dashevo/evo-sdk";
-
 import type { Logger } from "../lib/logger";
+import { loadSdkModule } from "./sdkModule";
 import type { DashKeyManager, DashSdk } from "./types";
 
 export const NOTE_SCHEMAS = {
@@ -78,6 +77,7 @@ export async function refreshContractCache({
   if (!contractId || typeof sdk.getWasmSdkConnected !== "function") return;
   const wasm = await sdk.getWasmSdkConnected();
   if (!wasm || typeof wasm.removeCachedContract !== "function") return;
+  const { Identifier } = await loadSdkModule();
   const identifier = new Identifier(contractId);
   try {
     wasm.removeCachedContract(identifier);
@@ -98,6 +98,7 @@ export async function registerContract({
   log?.("Registering Dashnote note contract…");
   const { identity, identityKey, signer } = await keyManager.getAuth();
   const identityNonce = await sdk.identities.nonce(identity.id.toString());
+  const { DataContract } = await loadSdkModule();
   const dataContract = new DataContract({
     ownerId: identity.id,
     identityNonce: (identityNonce || 0n) + 1n,

example-apps/dashnote/src/dash/createNote.ts

@@ -3,9 +3,8 @@
  *
  * SDK method: sdk.documents.create({ document, identityKey, signer })
  */
-import { Document } from "@dashevo/evo-sdk";
-
 import type { Logger } from "../lib/logger";
+import { loadSdkModule } from "./sdkModule";
 import type { DashKeyManager, DashSdk } from "./types";
 
 export interface CreateNoteParams {
@@ -27,6 +26,7 @@ export async function createNote({
 }: CreateNoteParams): Promise<string> {
   log?.("Creating note…");
   const { identity, identityKey, signer } = await keyManager.getAuth();
+  const { Document } = await loadSdkModule();
   const trimmedTitle = title?.trim();
   const document = new Document({
     properties: {

example-apps/dashnote/src/dash/sdkModule.ts

@@ -0,0 +1,17 @@
+// Defer the @dashevo/evo-sdk value import so it doesn't anchor the SDK chunk
+// to the entry graph via files statically imported by SessionContext /
+// LoginModal / NotesWorkspace. Cached after first call; cleared on failure
+// so a transient chunk fetch can retry.
+export type SdkModule = typeof import("@dashevo/evo-sdk");
+
+let sdkModulePromise: Promise<SdkModule> | null = null;
+
+export function loadSdkModule(): Promise<SdkModule> {
+  if (!sdkModulePromise) {
+    sdkModulePromise = import("@dashevo/evo-sdk").catch((err) => {
+      sdkModulePromise = null;
+      throw err;
+    });
+  }
+  return sdkModulePromise;
+}

example-apps/dashnote/src/dash/updateNote.ts

@@ -6,9 +6,8 @@
  *   sdk.documents.get(contractId, documentTypeName, documentId)
  *   sdk.documents.replace({ document, identityKey, signer })
  */
-import { Document } from "@dashevo/evo-sdk";
-
 import type { Logger } from "../lib/logger";
+import { loadSdkModule } from "./sdkModule";
 import type { DashKeyManager, DashSdk } from "./types";
 
 export interface UpdateNoteParams {
@@ -37,6 +36,7 @@ export async function updateNote({
     throw new Error(`Note ${noteId} not found.`);
   }
 
+  const { Document } = await loadSdkModule();
   const revision = BigInt(existingDoc.revision ?? 0) + 1n;
   const trimmedTitle = title?.trim();
   const document = new Document({