api(consistency): finish harmonized handler surface across remaining domains

[joshrotenberg]

Summary

The crate has started an ergonomics pass, but the public handler surface is still uneven. flexible::databases now has builders, pagination helpers, and simplified list/get/create/update/delete methods, while other domains still expose older verbose names, mixed return types, or raw serde_json::Value responses.

Why this matters

• users have to learn different naming schemes for equivalent operations
• docs/examples are harder to keep coherent
• Python parity work gets harder when the Rust surface is not internally consistent
• new endpoint additions are more likely to copy older patterns instead of the newer façade style

Examples of the inconsistency

Newer simplified style already exists

• src/flexible/databases.rs:2073
• src/flexible/databases.rs:2105
• src/flexible/databases.rs:2141
• src/flexible/databases.rs:2180
• src/flexible/databases.rs:2215
• src/fixed/subscriptions.rs:476
• src/fixed/databases.rs:803

Older or uneven surfaces still remain

• src/account.rs:449
• src/users.rs:193
• src/acl.rs:436
• src/cloud_accounts.rs:258
• src/tasks.rs:131
• src/connectivity/mod.rs:74
• src/connectivity/private_link.rs:277
• src/connectivity/psc.rs:177
• src/transit_gateway.rs equivalent methods in src/connectivity/transit_gateway.rs
• src/flexible/subscriptions.rs:906 and related methods still use older names without a fully harmonized alias layer

Suggested direction

• finish the harmonization plan across remaining handlers
• add simplified alias methods where there is a clear CRUD/list/get shape
• prefer typed return values over raw Value when the response is known
• keep existing method names as compatibility shims where needed, but make the simplified façade the documented/default API

Acceptance criteria

• each handler has a coherent public surface with consistent naming for equivalent operations
• CRUD-like handlers expose list/get/create/update/delete or an explicitly documented alternative
• raw Value return types are reduced to cases where the payload is genuinely dynamic
• README and rustdoc examples prefer the harmonized façade