…propagated

This commit fixes the propagation of the `detailed-tracing-attributes` flag
to all necessary annotation structs and updates the templates to correctly
utilize the flag.

Specifically:
- Adds `DetailedTracingAttributes` field to `modelAnnotations` and
  `serviceAnnotations` in `annotate.go` to make the flag accessible
  in `lib.rs.mustache` and service-level sections of `transport.rs.mustache`.
- Updates `annotateModel` and `annotateService` to populate the new fields.
- Adds comprehensive unit tests in `annotate_test.go` to verify the
  `DetailedTracingAttributes` flag is correctly set across `modelAnnotations`,
  `serviceAnnotations`, `methodAnnotation`, and `pathBindingAnnotation`
  based on the codec options.
- Modifies `lib.rs.mustache` to initialize the static
  `INSTRUMENTATION_CLIENT_INFO` using `std::sync::LazyLock` to accommodate
  the non-const `default()` function.
- Updates `transport.rs.mustache` to correctly dereference the `LazyLock`
  when calling `with_instrumentation` (i.e., `&*crate::info::INSTRUMENTATION_CLIENT_INFO`).

These changes ensure that the conditional code blocks in both `lib.rs.mustache`
and `transport.rs.mustache` related to detailed tracing are generated
correctly based on the `detailed-tracing-attributes` flag.

Tested:
  - Ran `go test -race ./...` in the librarian repository to ensure all
    unit tests pass, including new tests for flag propagation in annotations.
  - Manually regenerated the `google-cloud-showcase-v1beta1` client in a
    local `google-cloud-rust` clone using the modified librarian:
    1.  With `--codec-option=detailed-tracing-attributes=true`:
        - Verified `src/generated/showcase/src/lib.rs` contains the
          `INSTRUMENTATION_CLIENT_INFO` static (using `LazyLock`).
        - Verified `src/generated/showcase/src/transport.rs` includes
          `.with_instrumentation(&*crate::info::INSTRUMENTATION_CLIENT_INFO)`
          calls within the `if tracing_is_enabled` blocks in the `new`
          methods.
        - Confirmed the crate builds and tests pass:
          `cargo build -p google-cloud-showcase-v1beta1`
          `cargo test -p google-cloud-showcase-v1beta1`
    2.  With the flag off (default):
        - Verified the above tracing-specific code is absent.
    3.  By setting `detailed-tracing-attributes = "true"` in
        `src/generated/showcase/.sidekick.toml` and running refresh without
        the codec option, confirming the config file is also respected.