BX2 MK1: exact alias BX2 and two-outlet start on f006 byte 1

[matthewhand]

Fixes #8

Confirmed on BX2 Dual Outlet Bluetooth Tap Timer MK1 only (SKU CO3112):
https://www.holmanindustries.com.au/product/bx2-dual-outlet-bluetooth-tap-timer-mk1/

Not tested on the newer BX2:
https://www.holmanindustries.com.au/product/bx2-dual-outlet-bluetooth-tap-timer/

Summary

Two BX2 MK1 gaps in the Linux SDK:

1. Alias filter. Advertised name is exactly BX2. Discovery uses an exact-string allowlist: Tap Timer (existing BX1) and BX2. Empty alias does not match. Constructor accepted_aliases or HOLMAN_ACCEPTED_ALIASES (comma-separated) adds another exact name, not a prefix.

2. Second byte selects the outlet. Current start() is [0x01, 0x00, 0x00, minutes] with byte 1 hardcoded 0. Zone 1 (--zone 1) stays that payload. Zone 2 (--zone 2) is byte 1 = 0x01: [0x01, 0x01, 0x00, minutes]. Stop stays all-zero. The current CLI has no --zone; start() always writes byte 1 as 0.

start = [0x01, tap_index, 0x00, minutes]
tap_index 0 = zone 1  (--zone 1)
            1 = zone 2  (--zone 2)
stop  = [0x00, 0x00, 0x00, 0x00]

Some units expose c001. Writing AE 8E there first unlocks the session so the following f006 write is accepted. If c001 is missing, skip it.

HOLMAN_SERVICE_UUIDS (or constructor service_uuids) replaces the vendor UUID filter. Defaults stay CO3015 / CO3012 / CO3011.

This PR is the SDK change (holman/holman.py, holmanctl.py) plus a short README supported-devices note.

Test plan

• python3 -m py_compile holman/holman.py holmanctl.py
• TapTimer.start zone 1 -> 01 00 00 NN, zone 2 -> 01 01 00 NN
• holmanctl --help shows --zone 1 / --zone 2
• Discover accepts exact Tap Timer and BX2 only by default
• Unset HOLMAN_SERVICE_UUIDS keeps CO3015 / CO3012 / CO3011