Implement persistent typed database environments

[cloutiertyler]

Description of Changes

Implements typed environment variables with typed module accessors, persistent values, and a usage guide. Supports undeclared values, --env-only, explicit deletion, and --replace-env. Updates use module-publishing permissions and validate atomically against module declarations.

Creation and reset persist initial values before starting the replica. Rejected publishes preserve the running host; unchanged publishes remain no-ops. Cloud companion: SpacetimeDBPrivate#3940.

API and ABI breaking changes

Not breaking. Requires a minor version bump.

Extends V10 metadata and host imports. Extends the HTTP API to allow publishing environment variables when publishing a module. ENV-enabled modules require an updated host.

Rollback safety impact

n/a (no prerequisite PRs). Older hosts cannot run ENV-enabled modules. Standalone control DB row encodings are unchanged; re-upgrading ignores obsolete initial values left by an older server's reset. --delete-data clears environment values.

Expected complexity level and risk

4/5. Publication, persistence, secret access controls, and all four module libraries.

Testing

CLI smoke tests and module tests cover typed access, authorization, atomic updates, rejected publication, unchanged-publication no-ops, view refresh, restart/recovery, and legacy control DB reset compatibility.

[cloutiertyler]

I've really spent quite a while reviewing and testing this PR. I believe it's good to go, but this is still quite high risk, especially with changes to the control db and the host/module lifecycle.