The build-time COPY+RUN of patch_tts_tool.py failed because
the Dockerfile starts from debian:stable-slim and only copies
the ai/ build context — there's no tools/tts_tool.py in the
image at build time (Hermes is on the mounted data volume).
Move patching to fix-permissions.sh which runs at container
startup when the data volume is mounted, so tts_tool.py is
available via the venv site-packages.
Also make patch_tts_tool.py robust: searches multiple paths
for tts_tool.py, accepts path as argument, exits 0 instead
of 1 when file/pattern not found (build must not fail).
