feat: Show how safe a bank is for account holders

[ayushcmd]

Right now the dashboard is great for analysts but if someone
just wants to know "is my bank doing okay?" there's no simple answer.

Idea is to add a small safety summary for each bank based on
data we already have — NPA trend, CAR, profit consistency.
Turn that into a score and show it clearly on the Bank Deep Dive page.

Also want to add a note like "your deposits up to ₹5 lakh
are insured by DICGC" — most people don't know this.

To do:

• Figure out a simple scoring logic using NPA + CAR + ROE
• Show score with a color (green/yellow/red) — nothing fancy
• Add the DICGC insurance note somewhere visible