Use plugin-prefixed admin hooks and tighten test stubs

[happyloa]

Motivation

• Ensure admin-side filter hooks use a clear, plugin-specific prefix to avoid naming collisions and improve discoverability.
• Make test stubs safer and more realistic by applying proper escaping to template output.
• Avoid creating an unprefixed global WP_CLI class in tests which could conflict with the real environment.

Description

• Rename admin filter hooks to use the plugin prefix by changing siteadwa_main_admin_history_display to site_add_on_watchdog_admin_history_display in src/AdminPage.php.
• Rename the admin per-page filter in the admin template from siteadwa_main_admin_risks_per_page to site_add_on_watchdog_admin_risks_per_page in templates/admin-page.php.
• Improve the history template test stub to echo escaped output by changing the esc_html_e test alias to echo esc_html($text) in tests/RiskHistoryTest.php.
• Replace the unprefixed WP_CLI test stub with a prefixed Watchdog_WP_CLI class and add a class_alias to WP_CLI in tests/Cli/ScanCommandTest.php to avoid global name collisions.

Testing

• No automated test suite was executed as part of this change.
• Files modified: src/AdminPage.php, templates/admin-page.php, tests/Cli/ScanCommandTest.php, and tests/RiskHistoryTest.php.
• Local commit was created successfully containing these changes.
• Further CI or unit test runs are recommended to validate behavior in full environments.

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Codex Task