feat: add builder patterns to request structs

[joshrotenberg]

Summary

🎉 100% COMPLETE - This PR now implements builder patterns for ALL request structs across both redis-cloud and redis-enterprise libraries!

Achievement Unlocked: 100% Coverage! 🏆

Final Status

• ✅ redis-cloud: 6/6 structs (100%)
• ✅ redis-enterprise: 18/18 structs (100%)
• Total: 24/24 request structs have builders!

Changes Made

🏗️ Complete Builder Pattern Implementation

redis-cloud crate (6 structs):

• ✅ CreateDatabaseRequest / UpdateDatabaseRequest
• ✅ CreateSubscriptionRequest / UpdateSubscriptionRequest
• ✅ CloudProviderConfig / CloudRegionConfig
• ✅ CreateBackupRequest
• ✅ CreatePeeringRequest

redis-enterprise crate (18 structs):

HIGH Priority:

• ✅ CreateDatabaseRequest (migrated from custom builder to TypedBuilder)
• ✅ BootstrapRequest
• ✅ CreateMigrationRequest
• ✅ DebugInfoRequest

MEDIUM Priority:

• ✅ CreateUserRequest / UpdateUserRequest
• ✅ CreateRoleRequest with BdbRole
• ✅ CreateCrdbRequest with CreateCrdbInstance
• ✅ CreateScheduledJobRequest
• ✅ CreateLdapMappingRequest
• ✅ CreateSuffixRequest
• ✅ CreateRedisAclRequest
• ✅ CreateCrdbTaskRequest
• ✅ DiagnosticRequest

LOW Priority:

• ✅ ServiceConfigRequest
• ✅ NodeActionRequest
• ✅ LicenseUpdateRequest

🎯 Developer Experience Improvements

Before (verbose and error-prone):

let request = CreateDatabaseRequest {
    name: "example-db".to_string(),
    memory_limit_in_gb: 0.1,
    data_persistence: "none".to_string(),
    replication: false,
    data_eviction: Some("volatile-lru".to_string()),
    password: None,
    support_oss_cluster_api: Some(false),
    use_external_endpoint_for_oss_cluster_api: None,
};

After (clean and ergonomic):

let request = CreateDatabaseRequest::builder()
    .name("example-db")
    .memory_limit_in_gb(0.1)
    .data_persistence("none")
    .replication(false)
    .data_eviction("volatile-lru")
    .support_oss_cluster_api(false)
    .build();

🚀 Key Benefits

1. No more Some() wrapping - strip_option attribute handles this automatically
2. No more .to_string() calls - setter(into) converts &str to String
3. Cleaner optional fields - Only set what you need, defaults handle the rest
4. Better IDE support - Autocomplete shows available builder methods
5. Compile-time safety - Required fields enforced at build time
6. Consistent API - All request structs follow the same pattern
7. Backward compatible - Original struct constructors still work

Testing

• ✅ All builders compile successfully
• ✅ All 500+ tests pass
• ✅ Documentation examples updated
• ✅ Fixed test using deprecated API

Implementation Details

Used typed-builder v0.20 with consistent patterns:

• #[builder(setter(into))] for String fields
• #[builder(default, setter(into, strip_option))] for Option
• #[builder(default, setter(strip_option))] for other Option
• Default values for optional fields

What This Means

Every single request struct in both Redis libraries now has an ergonomic builder pattern! This makes the Redis APIs significantly more pleasant to use and maintains consistency across the entire codebase.

Closes #38
Closes #41