v1.8.6 - Hotfix P0: macaroon exp (ms vs s)

Hotfix P0 - Macaroon expiration units (ms vs s)

All real Lightning tokens were immediately rejected because providers stored exp in Unix seconds (~1.7B) while verify.ts compared against Date.now() in milliseconds (~1.7T).

Changes

• All 5 TS providers: exp: Date.now() + 3_600_000 (was Math.floor(Date.now()/1000) + 3600)
• All providers: AbortSignal.timeout() (15s createInvoice, 10s checkPayment)
• verify.ts: token length guard (>4096 chars rejected)

Also

• Docs: rate-limit guide, BudgetTracker concurrency warning, mock wallet snippet, testnet column
• VSCode extension v1.8.5: Pro status auto-refreshes within 30s of payment

Tests

478 TS / 127 Python / 20+ Go / 36 Rust - all passing

Upgrade immediately - v1.8.5 on npm is deprecated.