26.06

Added

• PCRE2, vdt: Add recipes for ROOT external dependencies (ROOT plans to
  drop its bundled copies)

Fixed

• ROOTEGPythia6: Switch to external pythia6 recipe; fix rootmap naming
  mismatch (libTPythia6 vs libEGPythia6); keep TPythia6 PCM filename so
  ROOT's auto-loading still finds it
• FairRoot: Support fmt 11.1+
• PCRE2, VDT: Export PCRE2_ROOT and VDT_ROOT and set CMP0144 so dependents
  resolve them

Changed

• ROOT: Update to v6-40-02, build against external PCRE2 and VDT instead
  of builtins
• GCC-Toolchain: Switch to upstream GCC 15.2.0 (was alisw/gcc-toolchain
  v13.2.0-alice1); required for std::from_range (C++23) used by PHLEX
• Geant4: Update to v11.4.2
• XRootD: Update to v6.0.3
• fmt: Update to v12.2.0
• zstd: Update to v1.5.7
• libffi: Update to v3.5.2
• Refresh pinned versions of python packages
• FairShip: Update to 26.06; drop unused python-uproot requirement and
  stale HEPMC_DIR / HEPMC_INCLUDE_DIR flags
• PCRE2, vdt: Use alibuild-generate-module for the modulefile

Full Changelog: 26.05...26.06