[Linux] Wait for A2DP profile enumeration before restarting WirePlumber

Problem

A newly connected Bluetooth card can appear before its A2DP profiles have been enumerated. The current activation path treats the first missing-profile result as a failure, restarts WirePlumber immediately, and then performs a single recheck that can race pipewire-pulse rebuilding the card.

Expected behavior

Give initial profile enumeration a short grace period. Keep WirePlumber restart as a last resort and use bounded retries while the card and profiles reappear afterward.

Acceptance criteria

• A temporarily incomplete card can become ready without a WirePlumber restart.
• Post-restart checks tolerate delayed card and profile enumeration.
• Retries are bounded and do not sleep again after the final failed attempt.
• A persistent failure is logged and returned without attempting profile activation.

Start at the Linux activation path for a newly connected Bluetooth card and trace how missing profiles trigger WirePlumber restart and the pipewire-pulse recheck. Confirm the change against the acceptance criteria: delayed enumeration succeeds without an unnecessary restart, post-restart retries are bounded without a final sleep, and persistent failure is logged and returned without profile activation.