When the radio does not report the TGXL via the amplifier API (observed
on Flex-8600 firmware 4.2.18), the TUN applet never appeared even though
the direct TCP connection on port 9010 was fully operational.

Root cause: presenceChanged(true) was only emitted from setHandle(), which
requires the radio to send "amplifier <handle> model=TunerGeniusXL".
The existing directConnectionChanged signal was emitted on direct TCP
connect but never wired to presenceChanged.

Fix (3 parts):

1. TunerModel: add m_directPresence flag, set it when direct TCP connects,
   emit presenceChanged(true/false) from the connected/disconnected lambdas.
   isPresent() now returns true if either the radio handle or direct
   connection is active. setHandle() uses isPresent() so clearing the
   handle does not hide the applet while a direct connection is live.

2. RadioModel: log every amplifier status handle + model at lcProtocol
   debug level. Previously unrecognised models were silently dropped,
   making firmware-variant bugs impossible to diagnose from logs.

3. RadioModel: handle amplifier removal via kvs.contains("removed"),
   clearing TunerModel handle or m_ampHandle/m_hasAmplifier as appropriate.
   Previously amplifier state was only cleared on radio disconnect.

Tested: Flex-8600 firmware 4.2.18.41174, TGXL firmware 1.1.20.
TUN applet now appears and relay/TUNE controls work. Operate/standby
via radio API requires a valid handle (not available when radio omits
the amplifier status) — tracked separately.

The radio sends object-removal status in two forms — verified against
FlexLib Radio.cs:14060/14073, which uses substring `s.Contains("removed")`
to handle both:

  1) bare:  "amplifier <handle> removed"        (no '=' anywhere)
  2) kvs:   "amplifier <handle> ... removed=1"  (key in kvs map)

Our CommandParser splits status on the last space before the first '=',
so form 1 lands entirely in `object` (kvs is empty), while form 2
splits normally and `removed` ends up as a kvs key.

The original PR only handled form 2. Form 1 is the form actually used
in observed protocol traffic (e.g. `S<h>|stream 0x04000008 removed`),
so add an `ampRemovedRe` regex check before the regular `ampRe` match.

This mirrors the pattern already used by `streamStatusRemoved` at
RadioModel.cpp:155-161.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>