Adopt the modern-di integration kit

[lesnik512]

Summary

modern-di 2.28.0 shipped modern_di.integrations — framework-agnostic primitives that formalize what this package's _DiMiddleware.consume_scope and Dependency/FromDI already hand-roll. This swaps the hand-rolled internals for kit calls. No public-API change; zero test-file changes.

Sixth of 13 planned adapter conversions (after starlette 2.2.0, fastapi 2.10.0, litestar 2.13.0, aiohttp 2.2.0, flask 2.1.0). FastStream combines traits from two prior conversions: like Flask, it has exactly one connection/message type (faststream.StreamMessage, broker-agnostic) so integrations.bind() is used directly with no classify_connection; unlike Flask, consume_scope wraps a single call site, so a Container async-context-manager block IS introduced. Like fastapi/litestar, FastStream has its own native DI seam (Depends), so there's no hand-rolled @inject to replace.

• consume_scope now derives scope/context via integrations.bind(faststream_message_provider, msg) and opens the child container via async with ... as request_container:, nested with the existing sync with self.context.scope(...): block. The dead import modern_di (bare module) is removed.
• Dependency's field renamed to marker: integrations.Marker[T_co]; __call__ delegates to self.marker.resolve(request_container). FromDI constructs Dependency(integrations.Marker(dependency)).
• architecture/dependency-injection.md promoted to describe the new internals.
• Bumps the modern-di floor to >=2.28,<3.

Test plan

• just test-ci — 100% line coverage, all 5 tests passing, zero test-file changes
• just lint-ci — ruff, ty, check-planning all clean
• Per-task spec + quality review (5 tasks, all approved)
• Whole-branch review (approved, no findings — including a traced verification that the new nested async-with/with structure preserves the original try/finally's exception-ordering)