fix(rds): add MySQL/MariaDB dump/restore, fix license model and metadata

[vieiralucas]

Summary

• Branch dump_database/restore_database by engine: mysqldump/mysql for MySQL/MariaDB, pg_dump/psql for PostgreSQL — read replicas and snapshot restores now work across all engines
• Return correct license model per engine (general-public-license for MySQL/MariaDB, postgresql-license for PostgreSQL)
• Make latest_restorable_time optional — omit XML element for instances with BackupRetentionPeriod=0
• Unify supported DB instance classes into single SUPPORTED_INSTANCE_CLASSES constant to prevent drift
• Use engine-appropriate default DB name (mysql vs postgres)

Addresses unresolved Cubic findings from PR #220.

Test plan

• cargo clippy --workspace --all-targets -- -D warnings passes
• All 14 RDS unit tests pass
• Full workspace compiles cleanly

---

Summary by cubic

Adds engine-aware dump/restore for RDS containers and fixes engine-specific metadata. Read replicas and snapshot restores now work for MySQL/MariaDB and PostgreSQL.

• New Features

  • Dump/restore now branches by engine (mysqldump/mysql vs pg_dump/psql).
  • Engine-appropriate default DB name (mysql vs postgres).

• Bug Fixes

  • Correct license model per engine (general-public-license for MySQL/MariaDB, postgresql-license for PostgreSQL).
  • latest_restorable_time is optional; omit XML when BackupRetentionPeriod=0, and set it for read replicas based on the source instance’s backup config.
  • Unified SUPPORTED_INSTANCE_CLASSES as a single source of truth.

^{Written for commit f2a1a91. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="crates/fakecloud-rds/src/service.rs">

<violation number="1" location="crates/fakecloud-rds/src/service.rs:1149">
P2: Set `latest_restorable_time` conditionally for read replicas so instances with `BackupRetentionPeriod=0` omit `LatestRestorableTime`.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}