ci: adopt estate CI standard — thin caller + wp-framework PHPUnit + 300-line split

- ci.yml: thin caller → peptide-e2e reusable (tests: wp-framework, has_js: true, line_limit_paths: inc)
- deploy.yml: retire standalone validate; gate deploy on ci.yml via workflow_call
- composer.json: test script → vendor/bin/phpunit (explicit)
- inc/helpers.php: split 311→211 lines; nav walker extracted to nav-walker.php
- inc/nav-walker.php: new — Peptide_Starter_Nav_Walker + menu fallback (123 lines)
- functions.php: require nav-walker.php before helpers.php; version 2.2.2→2.3.0
- style.css: version header 2.2.2→2.3.0
- package.json / package-lock.json: minimal npm manifest for lint-js job

Agent-Session: claude/adopt-ci-20260616

style.css

@@ -4,7 +4,7 @@ Theme URI: https://github.com/peptiderepo/peptide-starter
 Description: Premium, accessible WordPress theme for scientific peptide reference database
 Author: Peptide Repo
 Author URI: https://peptiderepo.com
-Version: 2.2.2
+Version: 2.3.0
 License: GPL v2 or later
 License URI: https://www.gnu.org/licenses/gpl-2.0.html
 Text Domain: peptide-starter