Add speech-first diff review mode with navigation and tests

config/settings/settings.conf

@@ -226,6 +226,15 @@ has_attributes=True
 # Shell to use for PTY emulation mode (empty = use system default shell)
 # Examples: /bin/bash, /bin/zsh, /usr/bin/fish
 shell=
+# Diff review presentation mode:
+# speech = spoken feedback only
+# sound = sound cues only (falls back to speech when cue is unavailable)
+# both = speech and sound cues
+diff_presentation=both
+# Diff review verbosity:
+# compact = concise role/location feedback
+# verbose = include diff line content during navigation
+diff_verbosity=compact
 
 [focus]
 # Follow and announce text cursor position changes