Fix opencode path: installer uses ~/.opencode/bin not ~/.local/bin

apps/harness/Dockerfile

@@ -42,8 +42,10 @@ RUN apk add --no-cache git github-cli curl ca-certificates
 RUN npm install -g @anthropic-ai/claude-code @openai/codex
 RUN curl -fsSL https://opencode.ai/install | sh || \
     echo "WARN: opencode install failed, skipping"
-# Ensure opencode is on PATH (installer puts it in ~/.local/bin which root owns)
-RUN if [ -f /root/.local/bin/opencode ]; then cp /root/.local/bin/opencode /usr/local/bin/opencode; fi
+# Ensure opencode is on PATH (installer may place it in ~/.opencode/bin or ~/.local/bin)
+RUN for p in /root/.opencode/bin/opencode /root/.local/bin/opencode; do \
+      if [ -f "$p" ]; then cp "$p" /usr/local/bin/opencode; break; fi; \
+    done
 
 # MCP servers: Gitea (Go binary from builder stage)
 COPY --from=gitea-mcp-builder /usr/local/bin/gitea-mcp /usr/local/bin/gitea-mcp