refactor(io)!: replace erased callbacks with typed model events

[johanpel]

Description

Replace generated AnyEvent and type-erased callback records with typed exporter providers.

• allow generated contexts to build exporters from any provider supporting each entity event type
• use umbrella-event conversions when one callback consumes events across a model
• make EventCallback<T> an exporter provider while preserving the full event envelope
• add Noop as the runtime-free provider
• migrate generated examples, legacy model contexts, query-engine tests, and NVTX consumers to the provider API

Written by Codex.

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR replaces optional exporter configuration with generic context providers, adds Noop, changes callbacks from erased recorded events to typed events, removes AnyEvent, updates generated observers, and migrates examples, tests, bridges, and integrations.

Changes

Instrumentation provider flow

Layer / File(s)	Summary
Provider-based context construction crates/instrumentation/src/..., crates/model/src/lib.rs, crates/model-macros/src/model_macro.rs	Contexts now accept generic ContextExporter providers. Noop handles disabled instrumentation. Context preparation and observer construction use the provider directly.
Typed callback exporter contract crates/io/callback/src/lib.rs, crates/io/src/..., crates/instrumentation/src/sidecar.rs, crates/instrumentation/Cargo.toml, crates/model/Cargo.toml	Callback exporters now use generic typed events and Into conversions. RecordedEvent and callback exporter options are removed.
Generated provider observers and umbrella events crates/instrumentation-build/src/..., crates/instrumentation-build/example/...	Generated models build observers from providers. AnyEvent generation is removed, and umbrella event generation is tested and used by the example.
Call-site and observer ownership migration crates/codegen/src/..., crates/instrumentation/tests/..., domains/query_engine/tests/fixed/..., examples/..., integrations/nvtx/example/...	Call sites pass providers or typed callbacks directly. Observer construction borrows shared exporter values instead of cloning or moving them.

Estimated code review effort: 4 (Complex) | ~60 minutes

Possibly related PRs

• rapidsai/quent#258: Introduced callback and simulator instrumentation paths updated by this PR.
• rapidsai/quent#400: Introduced AnyEvent generation removed by this PR.
• rapidsai/quent#518: Added umbrella-event work extended by this PR.

Suggested reviewers: mbrobbel, dhruv9vats, johallar

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: replacing erased callbacks with typed model events.
Description check	✅ Passed	The description clearly explains the refactor and its objectives, but it omits testing details and related issue information.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[johanpel]

/merge