test(smoke): fix three stale assertions (#3)

- 01 calculator: page lives at /calculator/ (confirmed live), not
  /reconstitution-calculator/ — the 404 failed all 3 calc tests.
- 00 homepage: brand title is 'Peptide Repo' (with space); regex /peptiderepo/i
  never matched. Broadened to /peptide ?repo/i.
- 03 admin: required-plugin slug is 'prautoblogger' (WP dir), not 'pr-autoblogger'.

These were test bugs, not site regressions — the site serves all three correctly.

Agent-Session: cto smoke-triage

Co-authored-by: peptiderepo <peptiderepo@users.noreply.github.com>

tests/01-reconstitution-calculator.spec.ts

@@ -14,7 +14,7 @@
 
 import { test, expect } from '@playwright/test';
 
-const CALC_PATH = process.env.CALC_PAGE_PATH ?? '/reconstitution-calculator/';
+const CALC_PATH = process.env.CALC_PAGE_PATH ?? '/calculator/';
 
 test.describe('Reconstitution Calculator', () => {
   test.beforeEach(async ({ page }) => {