Fix Soroban contract initialization, pure reads, and string bounds

[devfoma]

This PR resolves three critical issues regarding contract security, Soroban API interactions, and resource costs.

Changes

• Contract Initialization: Introduced an authenticated bootstrap authority for pool creation and initialization in both the repayment and pool contracts. This ensures a canonical trust boundary and prevents unauthorized takeovers.
• Pure Read Queries: Separated state-mutating keepalive operations from read-only pool queries. Pure read methods are now provided that execute without storage TTL side-effects, while legacy migrations and TTL renewals are moved to explicit, authorized keepalive operations.
• Contract String Bounds: Applied strict byte-length bounds on asset labels and reference inputs to prevent oversized inputs from causing excessive storage/event costs or exceeding Soroban resource limits.

Closes #163
Closes #179
Closes #169

[Obiajulu-gif]

Thanks for this PR! It currently has merge conflicts against main and can't be merged as-is. Could you rebase/merge main into your branch and resolve the conflicts? I'll take another look once it's conflict-free.

[Obiajulu-gif]

@devfoma resolve conflict and pr differently for the different else if will reflect in ur dashboard

[Obiajulu-gif]

This PR currently has merge conflicts with the base branch. Please update the branch from main, resolve the conflicts locally, and push the resolved changes so it can be merged.

[Obiajulu-gif]

I rechecked this PR against the current main branch and it still needs author/code-owner conflict resolution before it can be merged safely. The local merge hits broad conflicts including �pp/dashboard/admin/kyc-management/page.tsx, components/dashboard/sidebar.tsx, and add/add Soroban contract conflicts in contracts/chainmove-pool/src/lib.rs and contracts/repayment/src/lib.rs, along with a large stale branch delta. Because this requires deciding the current dashboard/sidebar and contract architecture, I am leaving it unmerged instead of guessing behavior on the author's behalf. Please rebase/merge current main, resolve those conflicts, and request another review.