remove CW decoder (audio->text) entirely; fix CWX macro not stopping on call typing

- Removes the RX-audio CW decoder: deletes app_cw.go + internal/cwdecode, the
  cwDecoder/cwPitchHz/cwMu/cwStop App fields, and all frontend state/effects, the
  header Ear button, the Tools menu item and the decoded-text strip. The CW
  KEYER (WinKeyer/Icom/Flex) is untouched.
- Fix: typing a callsign while a macro is keying now aborts the CURRENT engine
  (Flex CWX / Icom / WinKeyer) on the first character, not just WinKeyer during
  an auto-call loop — via a shared stopKeyerTx() helper.

app.go

@@ -32,7 +32,6 @@ import (
 	"hamlog/internal/clublog"
 	"hamlog/internal/cluster"
 	"hamlog/internal/contest"
-	"hamlog/internal/cwdecode"
 	"hamlog/internal/db"
 	"hamlog/internal/dxcc"
 	"hamlog/internal/email"
@@ -482,10 +481,6 @@ type App struct {
 
 	alertStore *alerts.Store // DX-cluster spot alert rules (global JSON)
 
-	cwMu           sync.Mutex        // guards the CW decoder lifecycle
-	cwStop         chan struct{}     // stops the CW decoder capture loop; nil when off
-	cwDecoder      *cwdecode.Decoder // live decoder (for retargeting the pitch)
-	cwPitchHz      int               // manual pitch override (0 = auto / follow Flex)
 	startupProfile string            // --profile <name> from the command line (activate at startup)
 	dvkRecSlot     int               // slot currently being recorded (DVKStartRecord → DVKStopRecord)
 	dvkPttKeyed    bool              // we keyed PTT for a voice message; unkey when it ends