feat: claude-auto-retry v0.1.0

Auto-retry Claude Code sessions when hitting Anthropic subscription rate limits.
Uses tmux monitoring + send-keys to detect rate limit messages, wait for reset,
and send "continue" automatically. Zero dependencies, zero workflow change.

- Shell wrapper intercepts `claude` command transparently
- Background monitor polls tmux pane for rate limit patterns
- Timezone-aware reset time parsing with DST safety
- Safe send-keys with foreground process verification
- --print mode: buffers output, retries cleanly for pipes
- Config validation prevents bad values from causing crashes
- 59 tests, 0 dependencies

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/config.js

@@ -0,0 +1,41 @@
+import { readFile } from 'node:fs/promises';
+import { join } from 'node:path';
+import { homedir } from 'node:os';
+
+export const DEFAULT_CONFIG = {
+  maxRetries: 5,
+  pollIntervalSeconds: 5,
+  marginSeconds: 60,
+  fallbackWaitHours: 5,
+  retryMessage: 'Continue where you left off. The previous attempt was rate limited.',
+  customPatterns: [],
+};
+
+const CONFIG_PATH = join(homedir(), '.claude-auto-retry.json');
+
+function validNumber(val, min, fallback) {
+  return typeof val === 'number' && Number.isFinite(val) && val >= min ? val : fallback;
+}
+
+function validate(cfg) {
+  cfg.maxRetries = validNumber(cfg.maxRetries, 1, DEFAULT_CONFIG.maxRetries);
+  cfg.pollIntervalSeconds = validNumber(cfg.pollIntervalSeconds, 1, DEFAULT_CONFIG.pollIntervalSeconds);
+  cfg.marginSeconds = validNumber(cfg.marginSeconds, 0, DEFAULT_CONFIG.marginSeconds);
+  cfg.fallbackWaitHours = validNumber(cfg.fallbackWaitHours, 0.1, DEFAULT_CONFIG.fallbackWaitHours);
+  if (typeof cfg.retryMessage !== 'string' || !cfg.retryMessage) {
+    cfg.retryMessage = DEFAULT_CONFIG.retryMessage;
+  }
+  if (!Array.isArray(cfg.customPatterns)) {
+    cfg.customPatterns = DEFAULT_CONFIG.customPatterns;
+  }
+  return cfg;
+}
+
+export async function loadConfig(path = CONFIG_PATH) {
+  try {
+    const raw = await readFile(path, 'utf-8');
+    return validate({ ...DEFAULT_CONFIG, ...JSON.parse(raw) });
+  } catch {
+    return { ...DEFAULT_CONFIG };
+  }
+}