v0.4.0

Add interval param to get_pnl_history tool (#6)

* feat: add interval param to get_pnl_history, default to 1d

Passes interval through to the API for server-side downsampling.
Defaults to '1d' so MCP consumers always get a manageable response.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: narrow interval type, document handler default

- Type interval as "1h" | "4h" | "1d" union instead of string
- Add comment explaining why ?? "1d" coexists with Zod .default()

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>