v0.1.1-alpha — the slider catches up

Second alpha snapshot, built from tested main at fec7253 (Build #327).

Highlights

• Foobar's volume slider can route hardware volume through the PCM helper's existing control connection.
• Tested M5 response drops to about a second, without a process or extra 55001 connection per slider update.
• Safer dB mapping, slider/menu synchronization, coalescing and volume cap handling.
• Shared CLI/connection plumbing and a substantially expanded test suite.

Still alpha

hardware_volume remains opt-in and volume_max keeps the hardware ceiling conservative (default 10). PR #48, which releases the speaker on stream teardown, is intentionally not included yet because it is still awaiting hardware validation.