Add position health factor calculation to reader contract

[abayomicornelius]

Problem

Users must manually calculate their liquidation risk. No convenient view function for health factor.

Why it matters

Poor UX leads to unexpected liquidations and user frustration.

Suggested fix

Add get_position_health_factor view returning 0-100% health score where <100% means liquidatable.

Acceptance criteria

• Add health factor calculation
• Include all fees in calculation
• Return user-friendly percentage
• Add to reader contract views

[mrmoney10010-design]

Hi! I'd like to work on this issue.

I'll implement a get_position_health_factor view that calculates and returns a user-friendly 0–100% health score, accounting for all applicable fees. I'll expose it through the reader contract, add comprehensive tests covering healthy and liquidatable positions, and update the relevant documentation to reflect the new view.

[Johnsource-hub]

@Johnsource-hub has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello, I’m a full stack developer with hands-on experience building with variety of tools including Nextjs, nodejs, nestjs, React, Typescript and more

I focus on writing clear, maintainable code and making sure features work as expected end to end, not just in isolation. I communicate progress regularly and keep things transparent as I work. I’m confident I can complete this task within an ETA of 4 HOURS

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Johnsource-hub to this issue.

[Carlys17]

@Carlys17 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I'd like to work on this.

Approach:
- Add get_position_health_factor view function to reader contract
- Calculate: (collateral_value - borrowed_value - fees) / liquidation_threshold * 100
- Include all protocol fees (origination, interest, liquidation penalty)
- Return percentage score where <100% = liquidatable
- Add to existing reader views alongside get_user_position, get_pool_stats

Files: contracts/reader/src/lib.rs, tests/reader_tests.rs

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Carlys17 to this issue.