feat(oracle): Enable alimentar data_store module (Refs #156)

- Add alimentar path dependency to depyler-oracle
- Enable data_store module for Parquet corpus storage
- Fix Array trait import for is_null method
- Fix synthetic corpus function name
- Tests: 313 passed, data_store roundtrip working

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: noahgift

crates/depyler-oracle/Cargo.toml

@@ -23,11 +23,10 @@ depyler-core = { path = "../depyler-core" }
 # Features: parallel (rayon), gpu (wgpu via trueno)
 aprender = { path = "../../../aprender", default-features = true }
 
-# Data loading and versioning (deferred - dependency conflicts)
-# TODO: Re-enable when aprender/alimentar are aligned
-# alimentar = "0.1.0"
-# arrow = { version = "53", default-features = false, features = ["prettyprint"] }
-# parquet = { version = "53", default-features = false, features = ["arrow", "snap"] }
+# Data loading and versioning
+alimentar = { path = "../../../alimentar" }
+arrow = { version = "53", default-features = false, features = ["prettyprint"] }
+parquet = { version = "53", default-features = false, features = ["arrow", "snap"] }
 
 # Serialization
 serde.workspace = true

crates/depyler-oracle/src/data_store.rs

@@ -8,7 +8,7 @@
 use crate::classifier::ErrorCategory;
 use crate::training::{TrainingDataset, TrainingSample};
 use alimentar::{ArrowDataset, Dataset};
-use arrow::array::{ArrayRef, RecordBatch, StringArray, UInt8Array};
+use arrow::array::{Array, ArrayRef, RecordBatch, StringArray, UInt8Array};
 use arrow::datatypes::{DataType, Field, Schema};
 use std::path::Path;
 use std::sync::Arc;
@@ -94,7 +94,6 @@ pub fn arrow_to_dataset(batch: &RecordBatch) -> TrainingDataset {
 
 /// Save training corpus to Parquet file.
 pub fn save_corpus(dataset: &TrainingDataset, path: &Path) -> crate::Result<()> {
-    use arrow::array::RecordBatchWriter;
     use parquet::arrow::ArrowWriter;
     use std::fs::File;
 
@@ -145,7 +144,7 @@ pub fn load_or_create_corpus() -> crate::Result<TrainingDataset> {
         load_corpus(path)
     } else {
         // Generate from hardcoded + synthetic
-        let dataset = crate::synthetic::build_augmented_corpus(0.5);
+        let dataset = crate::synthetic::generate_synthetic_corpus();
 
         // Save for next time
         if let Err(e) = save_corpus(&dataset, path) {

crates/depyler-oracle/src/lib.rs

@@ -20,7 +20,7 @@ pub mod citl_fixer;
 pub mod classifier;
 pub mod github_corpus;
 pub mod moe_oracle;
-// pub mod data_store; // TODO: Re-enable when alimentar integrated
+pub mod data_store;
 pub mod depyler_training;
 pub mod estimator;
 pub mod features;