feat: add shared messaging utils and surface real Claude CLI errors

[sean808080]

Problem

Claude CLI exits non-zero on auth and quota failures, but the human-readable error message (e.g. Not logged in · Please run /login) lives in the JSON stdout result field — not in stderr. All three chat bridges were showing Unknown error instead of the actual failure reason.

Before:

Error (exit 1): Unknown error

After:

Error (exit 1): Not logged in · Please run /login

Solution

Introduces src/messaging.ts — a shared utilities module used by start.ts, telegram.ts, and discord.ts.

Key function: extractErrorDetail(result)

export function extractErrorDetail(result: { stdout: string; stderr: string }): string {
  const stderr = result.stderr?.trim() || "";
  if (stderr) return stderr;

  // Claude CLI emits human-readable errors in JSON stdout when stderr is empty
  try {
    const parsed = JSON.parse(stdout);
    if (parsed?.is_error && parsed?.result) return String(parsed.result).trim();
    if (parsed?.error?.message) return String(parsed.error.message).trim();
    if (typeof parsed?.error === "string") return parsed.error.trim();
  } catch {}

  return stdout;
}

Additional utilities (no behaviour change, available for future use)

• describeProvider() — human-readable provider/model label
• isProviderStatusQuery() / isModelChangeRequest() — intent detection for model-switch queries
• authoritativeProviderReply() — canonical provider status response
• extractReactionDirective() — strips [react:emoji] directives from response text

Files changed

File	Change
src/messaging.ts	New shared utilities module
src/commands/start.ts	Use extractErrorDetail in forwardToTelegram and forwardToDiscord
src/commands/telegram.ts	Use extractErrorDetail in the main message handler error path
src/commands/discord.ts	Use extractErrorDetail in the main message handler error path

Testing

Auth failures now surface the real Claude CLI message across all three chat interfaces. The fix handles:

• stderr present → returns stderr (existing behaviour, unchanged)
• stderr empty, JSON stdout with is_error: true → returns result field
• stderr empty, JSON stdout with error.message → returns error.message
• Fallback to raw stdout if JSON parse fails