feat: add compare command for side-by-side token comparison (Fixes #23)

[lb1192176991-lab]

What

Adds a compare CLI command that runs rug_check_token on multiple mint addresses and displays a side-by-side ASCII comparison table in the terminal.

Why

Portfolio scanners, wallet analysis, and token research all involve comparing multiple tokens at once. Currently users must run solana-rug token N times and compare manually. This makes it a one-shot operation.

Implementation

New function: _format_comparison_table(reports, sort_by)

• Renders a clean ASCII table with auto-sized columns
• Rows include: Safety Score, Risk Level, Price, 24h Change, Liquidity, Volume, Holders, Top 10%, Warnings
• Sortable by: score (ascending, riskiest first), name, age, liquidity
• Falls back to "—" for missing data, no crashes

New CLI command: compare

• solana-rug compare <MINT1> <MINT2> [<MINT3> ...] — 2-20 tokens
• --json flag outputs JSON array instead of table
• --sort score|name|age|liquidity
• Graceful error handling: failed tokens show "ERROR" risk level, others continue

Test coverage (stdlib-only, no new deps)

• Two-token table rendering
• Sort-by-name ordering
• Empty list returns empty string

Example output

Metric       | RUG  | BONK
------------ | ---- | ----
Safety Score | 35   | 95
Risk Level   | HIGH | LOW
Price        | —    | —
24h Change   | —    | —
Liquidity    | —    | —
Volume 24h   | —    | —
Holders      | —    | —
Top 10%      | —    | —
Warnings     | 2    | 0

Fixes: #23

[codegraphtheory]

Sorry about this. The compare command was already merged in #42 from a different branch that had the same feature. Thank you for submitting and please try another bounty issue. We appreciate your contribution.