Add TypeScript submodule support for SpacetimeDB modules

[aasoni]

Add TypeScript submodule support for SpacetimeDB modules

Description of Changes

• TypeScript server SDK: runtime API for module mounting (submodules), including namespaced dispatch, ctx.as helpers for cross-namespace calls, and HTTP handler delegation
• TypeScript client codegen: namespace-aware table/reducer/procedure exports and query builder for submodule tables and views
• Migrations: auto-migrate support for submodule tables, views, and indexes; AddConstraint step added alongside NamespacedIdentifier-based migration steps
• CLI: namespace support for spacetime call and spacetime sql
• C++/C# bindings: autogenerated RawSubmoduleV10 types
• module-test-ts: submodule integration test (lib_submodule)

API and ABI breaking changes

Adds a submodule field to ModuleDef. Older modules will be publishable to new servers, but new modules that have submodules will not be publishable to old servers.

Expected complexity level and risk

5

Testing

Testing

Beyond the rust tests defined in this PR, the following tests were done on the full PR sequence once the entire namespace feature was implemented for typescript:
Feature Test Checklist

Module:

• root module can import another module and mount it with a namespace under its schema
• root module and submodule can have the same function and table names without conflicting
• ctx.db.lib.lib_table is readable/writable inside root module reducer
• ctx.db.lib.lib_table is readable/writable inside root module procedure withTx block
• library_reducer(ctx.as.lib) is callable inside root module reducer

Client

• Client can subscribe to lib.library_table
• Client can subscribe to lib.library_view
• Client can call lib/library_reducer
• Client can call lib/library_procedure
• Client can subscribe to lib.sublib.sublib_table
• Client can subscribe to lib.sublib.sublib_view
• Client can call lib/sublib/sublib_reducer
• Client can call lib/sublib/sublib_procedure

CLI

• CLI can subscribe to lib.library_table
• CLI can subscribe to lib.library_view
• CLI can call lib/library_reducer
• CLI can call lib/library_procedure
• CLI can subscribe to lib.sublib.sublib_table
• CLI can subscribe to lib.sublib.sublib_view
• CLI can call lib/sublib/sublib_reducer
• CLI can call lib/sublib/sublib_procedure

Migration

• Module migrates without issue from having a submodule to not having a submodule
• Module migrates without issue from not having a submodule to having a submodule
• Module migrates without issue when having a submodule and root module change occurs (change reducer signature, add table, add column with default, change reducer function body, change index)
• Module migrates without issue when having a submodule and a submodule change occurs (change reducer signature, add table, add column with default, change reducer function body, change index)

Commit Log

• Module loads fine from commit log
• Module snapshot is created without issue
• Module loads fine from snapshot