Fix build.sh: add proper escaping for nextcloud-mail ldflags

The build was failing with Go linker errors because special characters in
user-provided credentials (especially passwords) were not being properly escaped.

Added escape_ldflag() function to handle:
- Backslashes
- Double quotes
- Spaces

This ensures that any user input (including passwords with special characters)
is safely passed to Go's linker without breaking the build command.

build.sh

@@ -105,7 +105,28 @@ echo "✓ nextcloud-calendar built successfully"
 # Build nextcloud-mail
 echo "Building nextcloud-mail..."
 cd "$SCRIPT_DIR/tools/go/nextcloud-mail"
-go build -ldflags="-X main.BuildIMAPServer=$IMAP_SERVER -X main.BuildIMAPPort=$IMAP_PORT -X main.BuildIMAPUser=$IMAP_USER -X main.BuildIMAPPassword=$IMAP_PASS -X main.BuildSMTPServer=$SMTP_SERVER -X main.BuildSMTPPort=$SMTP_PORT -X main.BuildSMTPUser=$SMTP_USER -X main.BuildSMTPPassword=$SMTP_PASS -X main.BuildUseSSL=$USE_SSL -X main.BuildIgnoreCerts=$IGNORE_CERTS" -o ~/bin/nextcloud-mail .
+
+# Build ldflags - escape special characters in values
+escape_ldflag() {
+  local value="$1"
+  # Escape backslashes, double quotes, and spaces
+  value="${value//\\/\\\\}"
+  value="${value//\"/\\\"}"
+  echo "$value"
+}
+
+LDFLAGS="-X main.BuildIMAPServer=\"$(escape_ldflag "$IMAP_SERVER")\""
+LDFLAGS="$LDFLAGS -X main.BuildIMAPPort=\"$(escape_ldflag "$IMAP_PORT")\""
+LDFLAGS="$LDFLAGS -X main.BuildIMAPUser=\"$(escape_ldflag "$IMAP_USER")\""
+LDFLAGS="$LDFLAGS -X main.BuildIMAPPassword=\"$(escape_ldflag "$IMAP_PASS")\""
+LDFLAGS="$LDFLAGS -X main.BuildSMTPServer=\"$(escape_ldflag "$SMTP_SERVER")\""
+LDFLAGS="$LDFLAGS -X main.BuildSMTPPort=\"$(escape_ldflag "$SMTP_PORT")\""
+LDFLAGS="$LDFLAGS -X main.BuildSMTPUser=\"$(escape_ldflag "$SMTP_USER")\""
+LDFLAGS="$LDFLAGS -X main.BuildSMTPPassword=\"$(escape_ldflag "$SMTP_PASS")\""
+LDFLAGS="$LDFLAGS -X main.BuildUseSSL=\"$(escape_ldflag "$USE_SSL")\""
+LDFLAGS="$LDFLAGS -X main.BuildIgnoreCerts=\"$(escape_ldflag "$IGNORE_CERTS")\""
+
+go build -ldflags="$LDFLAGS" -o ~/bin/nextcloud-mail .
 echo "✓ nextcloud-mail built successfully"
 
 echo ""