feat(analytics): benchmark-aware portfolio health scoring

[DevMuhdishaq]

Closes #625
Portfolio health scoring and benchmark-aware rebalancing are now implemented
The analytics contract has been extended so portfolio advice now considers benchmark-relative performance and produces more actionable guidance.
Closes #627
What changed
Added benchmark tracking per property type in lib.rs
Updated get_rebalancing_suggestions to:
compare each asset’s trend against its benchmark,

Closes #629
adjust target allocation accordingly,
emit clearer recommendations such as overweight/underweight and benchmark lag guidance
Updated get_portfolio_health_score to reduce the score when a portfolio underperforms its benchmark, alongside existing diversification and concentration logic

Closes #632

[drips-wave]

@DevMuhdishaq Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits

[nanaf6203-bit]

🚀 Benchmark-aware portfolio health scoring is exactly what the analytics contract needed — overweight/underweight signals make rebalancing actually useful. Closes #625, #627, #629, #632. Squashing this in!