vibe-qc 0.4.5 — Schrödinger's Llama (Linux import + docs banner)

Two-fix patch release.

(1) docs/conf.py — landing-page banner on vibe-qc.com correctly
    identifies the release. Cherry-picks 01967df: load
    RELEASE_CODENAMES from python/vibeqc/banner.py via importlib
    so the CI build (which doesn't pip-install vibe-qc) still
    gets the catalogue. Banner now reads
    'Current release: 0.4.5 — Schrödinger's Llama'.

(2) Linux DT_RPATH vs DT_RUNPATH transitivity — import vibeqc
    still failed on Manjaro after v0.4.4 with
    ImportError: libcerfcpp.so.3. Two-prong fix:
      - cpp/CMakeLists.txt: -Wl,--disable-new-dtags on Linux
        forces transitive DT_RPATH for vibeqc_core.so.
      - scripts/build_libecpint.sh: -DCMAKE_INSTALL_RPATH='$ORIGIN'
        + BUILD_WITH_INSTALL_RPATH=ON; libecpint.so finds its own
        deps in the same install/lib via $ORIGIN.

No library code changes. 879 tests / 25 skipped / 1 xfailed at
v0.4.4 baseline.