feat: richer pnl reporting + CLI ergonomics polish

[tanem]

Summary

Two complete chunks of the read-views-and-reporting expansion (design: docs/superpowers/specs/2026-06-15-cli-read-views-and-reporting-design.md).

CLI ergonomics & polish bundle — drops the --json alias so --format table|json|csv is the single spelling, adds Examples sections to command help, enriches --version with commit and build date, adds --quiet/-q to silence stderr warnings, right-aligns numeric table columns via a manual table writer, shows the account currency in the pnl summary footer, and adds sign-based --color output (auto/always/never with TTY detection honouring NO_COLOR/TERM=dumb).

Phase 2 — richer reporting — splits net P&L into trade-profit/commission/swap/fee subtotals across every output, adds expectancy plus average and largest win/loss and a realised-P&L max drawdown to the summary, surfaces all of it in JSON and (rows-only) CSV, and replaces the old single-line summary with a two-group performance/breakdown block in table and JSON output.

Full-precision sums throughout; all display rounding stays in the render layer. README and CLAUDE.md are updated to match.

Test Plan

• go test ./... passes
• CI green across ubuntu/macos/windows (incl. -race)
• Eyeball the regenerated pnl_table.golden diff for alignment and the two-group block
• Spot-check pnl --format json|csv component subtotals sum to net
• Confirm --color auto detects a TTY and respects NO_COLOR

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 95.77836% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.14%. Comparing base (44047eb) to head (08c58cc).

Files with missing lines	Patch %	Lines
internal/render/render.go	90.72%	6 Missing and 8 partials ⚠️
cmd_accounts.go	89.47%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #7      +/-   ##
==========================================
+ Coverage   84.29%   89.14%   +4.85%     
==========================================
  Files          12       13       +1     
  Lines         452      783     +331     
==========================================
+ Hits          381      698     +317     
- Misses         64       71       +7     
- Partials        7       14       +7     

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