fix: use exact awk field matching for checksum lookup

Replace `grep "$EXPECTED_FILENAME" | awk '{print $1}'` with
`awk -v f="$EXPECTED_FILENAME" '$2 == f {print $1}'` to avoid
false matches when the filename appears as a substring in another
entry (e.g. matching 'gh-aw-linux-amd64-extra.tar.gz' when
searching for 'linux-amd64').

Agent-Logs-Url: https://github.com/github/gh-aw/sessions/057dcad8-6129-46c2-8ce5-d318e1698526

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Author: Copilot

actions/setup-cli/install.sh

@@ -335,8 +335,8 @@ if [ "$SKIP_CHECKSUM" = false ]; then
             EXPECTED_FILENAME="${PLATFORM}.exe"
         fi
 
-        # Extract the expected checksum from the checksums file
-        EXPECTED_CHECKSUM=$(grep "$EXPECTED_FILENAME" "$CHECKSUMS_PATH" | awk '{print $1}')
+        # Extract the expected checksum from the checksums file (exact filename match on field 2)
+        EXPECTED_CHECKSUM=$(awk -v f="$EXPECTED_FILENAME" '$2 == f {print $1}' "$CHECKSUMS_PATH")
 
         if [ -z "$EXPECTED_CHECKSUM" ]; then
             print_warning "Checksum for $EXPECTED_FILENAME not found in checksums file"