Auto-deploy skillset on container start for portable skill resolution

Add entrypoint logic to detect and run the skillset deploy script on
container start. Detection order: SKILLSET_CONTAINER_PATH env var,
then ~/skillset dedicated mount, then /workspace/skillset fallback.

The deploy script (from the skillset repo) creates relative symlinks
that resolve inside the container regardless of the host path layout.

Also adds SKILLSET_PATH volume mount option to docker-compose files
and documents SKILLSET_CONTAINER_PATH in .env.example for hosts where
the skillset lives in a workspace subdirectory.

entrypoint-user.sh

@@ -44,6 +44,28 @@ fi
 # generated) and no-ops if OPENCODE_PROVIDER is unset.
 python3 /usr/local/lib/opencode-devbox/generate-config.py
 
+# ── Skillset: deploy skills/instructions from mounted skillset repo ──
+# When the skillset repo is mounted (at $HOME/skillset or /workspace/skillset),
+# run the deploy script to create relative symlinks for skills and instructions.
+# This ensures skills resolve correctly inside the container regardless of
+# where the repo lives on the host. Idempotent — second run is a no-op.
+#
+# Detection order:
+#   1. SKILLSET_CONTAINER_PATH env var (explicit, for non-standard layouts)
+#   2. $HOME/skillset (dedicated volume mount via SKILLSET_PATH in compose)
+#   3. /workspace/skillset (skillset is directly inside workspace root)
+SKILLSET_DEPLOY=""
+if [ -n "${SKILLSET_CONTAINER_PATH:-}" ] && [ -x "${SKILLSET_CONTAINER_PATH}/deploy-skills.sh" ]; then
+  SKILLSET_DEPLOY="${SKILLSET_CONTAINER_PATH}/deploy-skills.sh"
+elif [ -x "$HOME/skillset/deploy-skills.sh" ]; then
+  SKILLSET_DEPLOY="$HOME/skillset/deploy-skills.sh"
+elif [ -x /workspace/skillset/deploy-skills.sh ]; then
+  SKILLSET_DEPLOY="/workspace/skillset/deploy-skills.sh"
+fi
+if [ -n "$SKILLSET_DEPLOY" ]; then
+  "$SKILLSET_DEPLOY" --bootstrap --prune-stale >/dev/null 2>&1 || true
+fi
+
 CONFIG_DIR="$HOME/.config/opencode"
 OMOS_CONFIG="$CONFIG_DIR/oh-my-opencode-slim.json"