fix(types): use .js extensions for shared-types re-exports

Commit 93bb94a12 dropped the extensions on shared-types re-exports
to make the web app's svelte-check pass (its tsconfig has no
allowImportingTsExtensions). That satisfied tsc but broke SSR: the
dev server tripped with ERR_MODULE_NOT_FOUND on every (app) route
because Node's native ESM loader (used by downstream tooling like
@tailwindcss/node) cannot resolve bare relative specifiers without
an extension, and only Vite-owned paths got the bundler-style
resolution the fix relied on.

Switch to the TypeScript-ESM idiomatic `.js` extension. tsc with
moduleResolution: "bundler" still type-checks against the actual
.ts source, and at runtime both Vite and Node resolve `.js` the
same way — no tsconfig flag flip required.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-types/src/index.ts

@@ -5,25 +5,25 @@
  */
 
 // Theme types
-export * from './theme';
+export * from './theme.js';
 
 // Auth types
-export * from './auth';
+export * from './auth.js';
 
 // UI types
-export * from './ui';
+export * from './ui.js';
 
 // Common utility types
-export * from './common';
+export * from './common.js';
 
 // Contact types for cross-app integration
-export * from './contact';
+export * from './contact.js';
 
 // Landing page configuration types
-export * from './landing-config';
+export * from './landing-config.js';
 
 // AI structured-output Zod schemas (shared between mana-api + web frontend)
-export * from './ai-schemas';
+export * from './ai-schemas.js';
 
 // API types
 export interface User {