fix(scripts): use case-sensitive match for acronym retention in PS branch names (#3130)

The branch-name generator keeps a short (<3 char) word only when it
appears in uppercase in the description, treating it as an acronym (the
comment says as much). The bash script uses a case-sensitive grep for
this, but the PowerShell script used -match, which is case-insensitive
by default. As a result every short non-stop word was retained on
PowerShell even when lowercase, so the same description produced
different branch names across the two shells (e.g. 'go AI now' ->
001-go-ai-now on PS vs 001-ai-now on bash).

Switch to -cmatch so the check is case-sensitive and the two shells
agree. Adds parity tests covering a dropped lowercase short word and a
kept uppercase acronym.

scripts/powershell/create-new-feature.ps1

@@ -111,8 +111,11 @@ function Get-BranchName {
         # Keep words that are length >= 3 OR appear as uppercase in original (likely acronyms)
         if ($word.Length -ge 3) {
             $meaningfulWords += $word
-        } elseif ($Description -match "\b$($word.ToUpper())\b") {
-            # Keep short words if they appear as uppercase in original (likely acronyms)
+        } elseif ($Description -cmatch "\b$($word.ToUpper())\b") {
+            # Keep short words only if they appear as uppercase in original (likely
+            # acronyms). Use -cmatch so the comparison is case-sensitive, matching the
+            # bash script's case-sensitive grep; -match would be case-insensitive and
+            # would keep every short word.
             $meaningfulWords += $word
         }
     }