Add Ticker Collision Brief skill

[SlumPark]

Adds a free standalone BankrBot skill for shared ticker lifecycle context.

• Aggregate-only output.
• No raw identifiers.
• No per-token rows.
• No ordering or prioritization.
• No authenticity resolution.
• No operator or entity attribution.
• No recommendations.
• No price predictions.
• Operator review required on every output.

Scope remains v0.1 boundary. No contract, hash, volume, liquidity, paid, or scanner features included.