fix: preserve WordPress cache headers for PHP responses

[SourovCodes]

Summary

• disable Nginx-generated one-hour browser cache headers for regular PHP responses
• disable the same unconditional browser cache policy in the FastCGI configuration
• preserve cache headers produced by WordPress

Why

expires 1h; modifies Expires and Cache-Control for every qualifying PHP response. This can make login, admin, REST, query-string, and FastCGI-bypassed responses browser-cacheable for one hour.

Using expires off; keeps browser cache policy under WordPress control. It does not disable FastCGI server-side caching.

Fixes #23

Validation

• git diff --check
• verified both PHP location configurations use the documented valid expires off; directive