fix: remove verbose tool logs from UI + symlink config/tht.yaml

Two fixes:
1. Revert tool_execution_* forwarding: these cluttered the UI with raw
   bash/read output the user never asked for. Only text_delta, system_event
   and ui_request are forwarded, as before.

2. tht ignores THT_CONFIG env var and always looks for config/tht.yaml
   relative to CWD. Create a symlink so the PI agent can run tht commands
   without -c flag.

docker/core.Dockerfile

@@ -43,6 +43,8 @@ RUN python -m venv /opt/venv \
     && /opt/venv/bin/pip install --no-cache-dir --upgrade pip \
     && (cd /app/harness && /opt/venv/bin/pip install --no-cache-dir .) \
     && cp /app/harness/workflow.yaml /opt/venv/lib/python3.12/site-packages/workflow.yaml
+# tht cerca config/tht.yaml relativo al CWD (ignora THT_CONFIG env). Symlink al workspace attivo.
+RUN mkdir -p /app/harness/config && ln -sf /app/harness/workspaces/local.yaml /app/harness/config/tht.yaml
 # PiProcessManager (backend) prepende harnessDir/.venv/bin al PATH del child Pi → symlink al venv reale
 RUN ln -s /opt/venv /app/harness/.venv