Flatten pub-use-star re-exports into explicit public API

[darinkishore]

Problem

Every mod.rs does pub use foo::* and lib.rs re-exports everything:

pub use adapter::chat::*;
pub use augmentation::*;
pub use core::*;
pub use data::*;
// ... etc

This makes the entire crate flat at the root — hundreds of items. Consequences:

• Name collisions (e.g. Prediction vs Predicted, DSRs ToolCall vs rig ToolCall)
• Impossible to tell what's public API vs internal
• IDE autocomplete noise
• Adding anything to any submodule automatically becomes public

Proposal

Move to explicit re-exports at the crate root:

// Core types users need
pub use core::{Module, Signature, Predict, Predicted, CallMetadata, PredictError, LM};
pub use core::signature::SignatureSchema;
// ... etc

Keep pub mod for submodules so users can reach internals via dspy_rs::core::whatever if needed, but the root namespace should be curated.

Impact

• Breaking change for downstream code that relies on flat imports
• But the crate is pre-1.0, so this is the time to do it

[darinkishore]

Codebase audit — current re-export surface

lib.rs lines 100-112:

pub use adapter::chat::*;
pub use augmentation::*;
pub use core::*;
pub use data::dataloader::*;
pub use data::prediction::*;
pub use data::serialize::*;
pub use data::utils::*;
pub use evaluate::*;
pub use modules::*;
pub use optimizer::*;
pub use predictors::*;
pub use utils::*;

Plus each mod.rs does its own pub use *:

• core/mod.rs → pub use lm::*; pub use module::*; pub use specials::*; pub use settings::*; etc.
• data/mod.rs → pub use dataloader::*; pub use example::*; pub use prediction::*; etc.

This creates a flat namespace at crate root with name collisions already present (DSRs ToolCall vs rig ToolCall).

Proposed curated root exports:

// Types every user needs
pub use core::signature::Signature;
pub use core::module::Module;
pub use core::schema::SignatureSchema;
pub use core::predicted::{Predicted, CallMetadata};
pub use core::errors::{PredictError, ParseError, LmError};
pub use core::lm::LM;
pub use core::settings::configure;
pub use predictors::predict::Predict;
pub use predictors::example::Example;
pub use modules::chain_of_thought::ChainOfThought;
pub use augmentation::WithReasoning;
pub use evaluate::{TypedMetric, evaluate_trainset};
pub use optimizer::{Optimizer, COPRO, GEPA, MIPROv2};
pub use data::dataloader::DataLoader;

// Keep pub mod for everything so users CAN reach internals
pub mod adapter;
pub mod core;
// ...

Breaking change scope: Any downstream code using use dspy_rs::* that relied on internal types being at root level. But the crate is pre-1.0 and the downstream user count is small. Better to do this now.

Approach: do it in one PR. cargo check against all tests/examples will catch everything that breaks. Most fixes will be adding a module path prefix.