fix(build): the wordmark number counts commits again, not compiles

GenerateBuildStamp read BuildCounter.txt, added 1 and wrote it back on every CoreCompile, so
the number tracked BUILDS: a day of iteration reached #1122 against 563 commits. It now uses
git rev-list count of HEAD, which is what the comment always claimed (and why the file existed
in .gitignore). No counter file, no drift; a missing git still falls back to the start.

Also moves the MIC and lip-sync volume bars up one line: both were pinned to the floor of their
bay by a star row plus VerticalAlignment=Bottom. They now sit directly under their headers,
with the auto rows sized to content.

.gitignore

@@ -20,7 +20,7 @@ MARCOM.md
 CREDENTIALS.md
 .aider*
 ffmpeg/
-BuildCounter.txt
+BuildCounter.txt  # unused since 2026-11-01 (the build stamp is the git commit count)
 
 # Steamworks runtime (steam_api64.dll, 312 KB) — extracted from the SDK zip, never committed;
 # scripts/steam-sdk.sh documents which file and why. Same rule as ffmpeg/: the pin is the audit trail.