feat: grant expiration management (#155), organization profiles (#156)

[ZacLou]

Summary

This PR implements two GrantFox Third Campaign issues:

Issue #155: Create a Grant Expiration Management System

• Created expiration-management.ts with auto-expiration detection
• isExpired() checks deadline + grace period (1 hour)
• isApproachingDeadline() identifies tasks within 24h of deadline
• checkExpirations() batch check returns expired + upcoming
• filterOutExpired(), getActiveTasks(), getExpiredTasks() for listings
• getExpirationStatus() determines correct terminal status
• Skips terminal statuses (completed/cancelled) from expiration

Issue #156: Add Organization Profiles for Grant Providers

• Created organization-profile.ts with full CRUD
• createOrganization() with duplicate name checking (case-insensitive)
• getOrganization(), getOrganizationByName() lookups
• listOrganizations(), listOrganizationsByAdmin() views
• updateOrganization() (admin-only with auth check)
• verifyOrganization() (platform-level verification)
• incrementGrantCount() / decrementGrantCount() for linking
• findAndLinkGrant() find org by name and auto-increment count

API Routes

• GET/POST /api/organizations - list, create (with optional admin filter)

Tests

• 8 tests for expiration management
• 10 tests for organization profiles

Closes #155
Closes #156