[codex] Resolve Meson wrap fallback policy for wirelog

[justinjoy]

Summary

• Prefer system wirelog >= 0.50.0 and libchronoid >= 1.0.2 before using Meson wraps.
• Use Meson wraps only as fallback, with explicit handling for nofallback, forcefallback, and force_fallback_for even though the upstream subprojects do not export Meson fallback dependency variables.
• Pin the wirelog wrap fallback to v0.50.0.
• Treat top-level nanoarrow and xxhash redirect wraps as untracked Meson leftovers only when they point into wirelog/subprojects, since those dependencies are owned by wirelog.

Closes #337

Validation

• tools/check-supply-chain-pins.sh .
• WYL_SUPPLY_CHAIN_REQUIRE_PACKAGECACHE=1 tools/check-supply-chain-pins.sh . fails as expected on pre-existing missing DuckDB packagecache archives.
• Clean worktree system-first path:
  • meson setup build-system --wrap-mode=nofallback -Denable_audit=disabled -Denable_fact_store=disabled
  • meson compile -C build-system
  • meson test -C build-system --print-errorlogs -> 70 OK, 0 failed, 2 skipped
• Clean worktree fallback path:
  • meson setup build-fallback --wrap-mode=forcefallback -Denable_audit=disabled -Denable_fact_store=disabled
  • confirmed subprojects/wirelog checked out v0.50.0
  • meson compile -C build-fallback wyrelog/wyctl
• PR CI on commit 07fd9b2 passed for Ubuntu, macOS, and Windows.