fast-xdebug 0.4.0 — easy install + smart auto-config

Focus: make it headache-free to install and configure.

Install everywhere — PIE (prefers a prebuilt binary, falls back to source), prebuilt Linux .so attached to this release (PHP 8.2-8.5, NTS/ZTS), a zero-config install.sh, manual source build, or a PECL .tgz. See the README install matrix. (Prebuilt binaries are attached by the release-binaries CI workflow shortly after this tag.)

Smart auto-config (heuristic, opt-in) — xdebug.mode=auto resolves coverage/profile from environment signals (test runner, XDEBUG_* env); explicit modes always win. fast_xdebug_recommended_settings() advises settings from memory_limit/CPU/opcache; fast_xdebug_resolved_mode() shows what auto chose.

Automatic memory guard — path-enumeration cap scales with memory_limit and is skipped above 85% live usage (branches + lines stay intact), so large suites never OOM. Disable with fast_xdebug.memory_guard=0.

Validated: 12/12 tests on PHP 8.2-8.5, valgrind-clean, php-code-coverage Cobertura unchanged. Step debugging still not implemented (documented).