fix: make bootstrap glob discovery portable

[chubes4]

Summary

• replace brace-expansion bootstrap discovery with separate portable class and interface glob patterns
• keep version-skew symbol top-up behavior unchanged without depending on optional PHP glob flags
• guard the existing version-skew regression against reintroducing GLOB_BRACE

Root cause

The already-loaded/version-skew bootstrap path passed GLOB_BRACE unconditionally. That flag is optional and is not defined by PHP-WASM, so evaluating the argument fatally failed before plugin activation could complete.

Plain glob() wildcard matching is the core PHP primitive needed here. Running one pattern for class-*.php and one for interface-*.php discovers the same files without libc brace-expansion support, downstream shims, or runtime coupling.

Validation

• php tests/bootstrap-version-skew-smoke.php
• composer smoke
• composer phpstan
• composer validate --strict
• PHP syntax checks for both changed files
• compared portable discovery against brace discovery on normal PHP: identical 202-file set
• WP Codebox 0.12.29 / Playground PHP-WASM / WordPress nightly activation probe: succeeded (run_ca3fad443dcd4f9b8b0eab3a3f32d0e9)
• preserved activation artifact bundle: sha256:0bcb94af5bbd829575820c3e890305fc3a3a4fe2a5fcc463a93f4426918040d5

Fixes #459