fix(opencode): ensure opencode binary is in PATH

- Check if opencode binary exists at expected location before symlinking
- Add ~/.opencode/bin to PATH in /etc/profile and /root/.bashrc
- Provides warning if binary not found instead of silently failing

Quality gates: code review

apps/api/src/main.py

@@ -170,7 +170,14 @@ services:
     command: >
       sh -c "apt-get update && apt-get install -y curl git tar &&
              curl -fsSL https://opencode.ai/install | bash &&
-             ln -sf $HOME/.opencode/bin/opencode /usr/local/bin/opencode &&
+             OPCODE_BIN=$HOME/.opencode/bin/opencode &&
+             if [ -f $OPCODE_BIN ]; then
+               ln -sf $OPCODE_BIN /usr/local/bin/opencode
+               echo 'export PATH=\"$HOME/.opencode/bin:$PATH\"' >> /etc/profile
+               echo 'export PATH=\"$HOME/.opencode/bin:$PATH\"' >> /root/.bashrc
+             else
+               echo 'Warning: opencode binary not found at expected location'
+             fi &&
              mkdir -p /workspace &&
              echo 'OpenCode installed. Run: opencode' &&
              tail -f /dev/null"