[rajtik76]

Fixes #107

What and why

Loads the imap extension that flock-php/binaries#48 adds to the PHP builds.

• imap is added to the extensions Flock loads from ext/ when present. On Windows 8.1–8.3 the official build already ships php_imap.dll, so it loads there right away.
• imap isn't thread-safe. The macOS and Linux FrankenPHP builds don't ship it, but on Windows FrankenPHP shares the official build's ext/, so php.ThreadUnsafeExtensions keeps it out of FrankenPHP's ini.
• docs/php.md lists imap and the FrankenPHP and Kerberos limits.

How I tested it

• New TestExtensionsIniSkipsThreadUnsafeForFrankenPHP. go test ./internal/php ./internal/frankenphp passes on Linux and on Windows; go run ./tools/docslint passes.
• CI on my fork: Build, all jobs green.
• The builds from php: add the imap extension binaries#48, tested there with the official imap test suite.

[Copilot]

🟢 Approval recommended

The review has no active issues for the IMAP-loading and FrankenPHP-exclusion changes.

No open issues 🎉

What changed in this PR

Adds automatic loading of bundled IMAP extensions for regular PHP, supporting #107, while excluding IMAP from FrankenPHP because it is not thread-safe.

Changes:

• Adds IMAP to extension loading and introduces a skip list used by FrankenPHP.
• Adds a test covering normal loading and thread-unsafe extension exclusion.
• Documents IMAP availability and its FrankenPHP and Kerberos limitations.

File	Description
internal/​php/​php.go	Adds IMAP loading and optional extension exclusions.
internal/​php/​php_test.go	Tests IMAP loading and exclusion while preserving other extensions.
internal/​frankenphp/​frankenphp.go	Excludes thread-unsafe extensions from generated FrankenPHP configuration.
docs/​php.md	Lists IMAP and documents its limitations.

_{Review effort: Balanced}

[lukas-frey]

Please see my reply in #107