Align UART completion with SSH behavior

src/console_completion.c

@@ -4,6 +4,7 @@
 #include "console_completion.h"
 
 #include <stddef.h>
+#include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -327,15 +328,34 @@ static ssize_t console_read_with_late_terminal_upgrade(int file_descriptor,
     return received;
 }
 
-static bool add_linenoise_completion(const char *candidate, void *context)
-{
-    linenoiseAddCompletion(context, candidate);
-    return true;
-}
+/* The UART frontend is the sole caller of linenoise's completion callback. */
+static char s_uart_completion_output[2048U];
 
 static void console_completion_callback(const char *buffer, linenoiseCompletions *completions)
 {
-    console_completion_visit(buffer, add_linenoise_completion, completions);
+    char completed[257U] = {0};
+    if (console_completion_expand(buffer, completed, sizeof(completed))) {
+        linenoiseAddCompletion(completions, completed);
+        return;
+    }
+
+    size_t output_length = 0U;
+    if (!console_completion_format_matches(buffer, s_uart_completion_output,
+                                           sizeof(s_uart_completion_output),
+                                           &output_length) ||
+        output_length == 0U) {
+        return;
+    }
+
+    /*
+     * Linenoise cycles every completion it receives. Print the shared list
+     * ourselves, then return the unchanged line as its one completion so its
+     * normal refresh restores the prompt without selecting a candidate.
+     */
+    fputs("\r\n", stdout);
+    (void)fwrite(s_uart_completion_output, 1U, output_length, stdout);
+    fflush(stdout);
+    linenoiseAddCompletion(completions, buffer);
 }
 
 void console_completion_install(void)