v0.2.8

Tunable rate-limit retry + bumped defaults

Pi auto-retries transient model errors (429 rate limit, 503 overloaded, 5xx, network/timeout) with exponential backoff, but its stock schedule (3 retries ≈ 14s) was too short for providers that limit on a per-minute window — notably Fireworks, whose TPM limits can take ~60s to clear, causing bursts to fail.

• Bumped default to 5 retries / 4s base → 4s, 8s, 16s, 32s, 64s (the final wait alone outlasts a 60s window).
• New flags --max-retries <n> (0 disables) and --retry-base-delay-ms <ms>; run() gains maxRetries / retryBaseDelayMs.
• Precedence: flag → operator ~/.pi/agent/settings.json retry block → agentic-pi default (operator config, incl. retry.provider.*, is preserved).
• Pauses remain observable via the existing auto_retry_start / auto_retry_end JSONL events.

See PR #5.