refactor: remove catalog re-export modules (#131)

## Summary
Addresses code review feedback from PR #130 by removing redundant
re-export modules and updating imports to use `lance_graph_catalog`
directly.

## Changes
- Removed `crates/lance-graph/src/namespace/` directory (only contained
re-exports)
- Removed `crates/lance-graph/src/source_catalog.rs` (only contained
re-exports)
- Updated `lib.rs` to re-export catalog types directly from
`lance_graph_catalog`
- Updated all internal imports in datafusion_planner, query, and Python
bindings to use `lance_graph_catalog`

## Test plan
- [x] `cargo check --all` passes
- [x] `cargo test --all` passes (all 4 doc tests pass, all unit tests
pass)

Resolves review comments from #130

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: beinan

crates/lance-graph/src/datafusion_planner/config_helpers.rs

@@ -10,7 +10,7 @@ use super::analysis::PlanningContext;
 use super::DataFusionPlanner;
 use crate::config::{NodeMapping, RelationshipMapping};
 use crate::error::Result;
-use crate::source_catalog::GraphSourceCatalog;
+use lance_graph_catalog::GraphSourceCatalog;
 use std::sync::Arc;
 
 impl DataFusionPlanner {

crates/lance-graph/src/datafusion_planner/join_ops.rs

@@ -14,10 +14,10 @@ use crate::ast::{PropertyValue, RelationshipDirection};
 use crate::case_insensitive::qualify_column;
 use crate::config::{NodeMapping, RelationshipMapping};
 use crate::error::Result;
-use crate::source_catalog::GraphSourceCatalog;
 use datafusion::logical_expr::{
     col, BinaryExpr, Expr, JoinType, LogicalPlan, LogicalPlanBuilder, Operator, TableSource,
 };
+use lance_graph_catalog::GraphSourceCatalog;
 use std::collections::HashMap;
 use std::sync::Arc;
 

crates/lance-graph/src/datafusion_planner/mod.rs

@@ -32,8 +32,8 @@ pub use analysis::{PlanningContext, QueryAnalysis, RelationshipInstance};
 use crate::config::GraphConfig;
 use crate::error::Result;
 use crate::logical_plan::LogicalOperator;
-use crate::source_catalog::GraphSourceCatalog;
 use datafusion::logical_expr::LogicalPlan;
+use lance_graph_catalog::GraphSourceCatalog;
 use std::sync::Arc;
 
 /// Planner abstraction for graph-to-physical planning

crates/lance-graph/src/datafusion_planner/scan_ops.rs

@@ -9,8 +9,8 @@ use super::analysis::{PlanningContext, RelationshipInstance};
 use crate::ast::PropertyValue;
 use crate::case_insensitive::qualify_column;
 use crate::error::Result;
-use crate::source_catalog::GraphSourceCatalog;
 use datafusion::logical_expr::{col, BinaryExpr, Expr, LogicalPlan, LogicalPlanBuilder, Operator};
+use lance_graph_catalog::GraphSourceCatalog;
 use std::collections::{HashMap, HashSet};
 use std::sync::Arc;
 
@@ -107,7 +107,7 @@ impl DataFusionPlanner {
         // No catalog attached - create empty source fallback for flexibility
         // This allows planners created with DataFusionPlanner::new() to work
         // without requiring a catalog, though they won't have actual data sources
-        let empty_source = Arc::new(crate::source_catalog::SimpleTableSource::empty());
+        let empty_source = Arc::new(lance_graph_catalog::SimpleTableSource::empty());
         let normalized_label = label.to_lowercase();
         let builder =
             LogicalPlanBuilder::scan(&normalized_label, empty_source, None).map_err(|e| {

crates/lance-graph/src/datafusion_planner/test_fixtures.rs

@@ -5,8 +5,8 @@
 
 use crate::config::GraphConfig;
 use crate::logical_plan::LogicalOperator;
-use crate::source_catalog::{InMemoryCatalog, SimpleTableSource};
 use arrow_schema::{DataType, Field, Schema};
+use lance_graph_catalog::{InMemoryCatalog, SimpleTableSource};
 use std::sync::Arc;
 
 pub fn person_schema() -> Arc<Schema> {
@@ -17,7 +17,7 @@ pub fn person_schema() -> Arc<Schema> {
     ]))
 }
 
-pub fn make_catalog() -> Arc<dyn crate::source_catalog::GraphSourceCatalog> {
+pub fn make_catalog() -> Arc<dyn lance_graph_catalog::GraphSourceCatalog> {
     let person_src = Arc::new(SimpleTableSource::new(person_schema()));
     let knows_schema = Arc::new(Schema::new(vec![
         Field::new("src_person_id", DataType::Int64, false),

crates/lance-graph/src/lib.rs

@@ -43,18 +43,18 @@ pub mod error;
 pub mod lance_native_planner;
 pub mod lance_vector_search;
 pub mod logical_plan;
-pub mod namespace;
 pub mod parser;
 pub mod query;
 pub mod semantic;
 pub mod simple_executor;
-pub mod source_catalog;
 
 /// Maximum allowed hops for variable-length relationship expansion (e.g., *1..N)
 pub const MAX_VARIABLE_LENGTH_HOPS: u32 = 20;
 
 pub use config::{GraphConfig, NodeMapping, RelationshipMapping};
 pub use error::{GraphError, Result};
+pub use lance_graph_catalog::{
+    DirNamespace, GraphSourceCatalog, InMemoryCatalog, SimpleTableSource,
+};
 pub use lance_vector_search::VectorSearch;
-pub use namespace::DirNamespace;
 pub use query::{CypherQuery, ExecutionStrategy};

crates/lance-graph/src/namespace/directory.rs

@@ -8,13 +8,13 @@ use crate::ast::ReadingClause;
 use crate::config::GraphConfig;
 use crate::error::{GraphError, Result};
 use crate::logical_plan::LogicalPlanner;
-use crate::namespace::DirNamespace;
 use crate::parser::parse_cypher_query;
 use crate::simple_executor::{
     to_df_boolean_expr_simple, to_df_order_by_expr_simple, to_df_value_expr_simple, PathExecutor,
 };
 use arrow_array::RecordBatch;
 use arrow_schema::{Field, Schema, SchemaRef};
+use lance_graph_catalog::DirNamespace;
 use lance_namespace::models::DescribeTableRequest;
 use std::collections::{HashMap, HashSet};
 use std::sync::Arc;
@@ -395,8 +395,8 @@ impl CypherQuery {
         &self,
         ctx: datafusion::execution::context::SessionContext,
     ) -> Result<arrow::record_batch::RecordBatch> {
-        use crate::source_catalog::InMemoryCatalog;
         use datafusion::datasource::DefaultTableSource;
+        use lance_graph_catalog::InMemoryCatalog;
         use std::sync::Arc;
 
         let config = self.require_config()?;
@@ -463,7 +463,7 @@ impl CypherQuery {
     /// ```ignore
     /// use std::sync::Arc;
     /// use datafusion::execution::context::SessionContext;
-    /// use lance_graph::source_catalog::InMemoryCatalog;
+    /// use lance_graph::InMemoryCatalog;
     /// use lance_graph::query::CypherQuery;
     ///
     /// // Create custom catalog
@@ -481,7 +481,7 @@ impl CypherQuery {
     /// ```
     pub async fn execute_with_catalog_and_context(
         &self,
-        catalog: std::sync::Arc<dyn crate::source_catalog::GraphSourceCatalog>,
+        catalog: std::sync::Arc<dyn lance_graph_catalog::GraphSourceCatalog>,
         ctx: datafusion::execution::context::SessionContext,
     ) -> Result<arrow::record_batch::RecordBatch> {
         use arrow::compute::concat_batches;
@@ -557,12 +557,12 @@ impl CypherQuery {
         &self,
         datasets: HashMap<String, arrow::record_batch::RecordBatch>,
     ) -> Result<(
-        crate::source_catalog::InMemoryCatalog,
+        lance_graph_catalog::InMemoryCatalog,
         datafusion::execution::context::SessionContext,
     )> {
-        use crate::source_catalog::InMemoryCatalog;
         use datafusion::datasource::{DefaultTableSource, MemTable};
         use datafusion::execution::context::SessionContext;
+        use lance_graph_catalog::InMemoryCatalog;
         use std::sync::Arc;
 
         if datasets.is_empty() {
@@ -619,13 +619,13 @@ impl CypherQuery {
         &self,
         namespace: std::sync::Arc<dyn lance_namespace::LanceNamespace + Send + Sync>,
     ) -> Result<(
-        crate::source_catalog::InMemoryCatalog,
+        lance_graph_catalog::InMemoryCatalog,
         datafusion::execution::context::SessionContext,
     )> {
-        use crate::source_catalog::InMemoryCatalog;
         use datafusion::datasource::{DefaultTableSource, TableProvider};
         use datafusion::execution::context::SessionContext;
         use lance::datafusion::LanceTableProvider;
+        use lance_graph_catalog::InMemoryCatalog;
         use std::sync::Arc;
 
         let config = self.require_config()?;
@@ -740,7 +740,7 @@ impl CypherQuery {
     /// Internal helper to explain the query execution plan with explicit catalog and session context
     async fn explain_internal(
         &self,
-        catalog: std::sync::Arc<dyn crate::source_catalog::GraphSourceCatalog>,
+        catalog: std::sync::Arc<dyn lance_graph_catalog::GraphSourceCatalog>,
         ctx: datafusion::execution::context::SessionContext,
     ) -> Result<String> {
         // Create all plans (phases 1-4)
@@ -757,7 +757,7 @@ impl CypherQuery {
     /// DataFusion logical planning) without creating the physical plan.
     fn create_logical_plans(
         &self,
-        catalog: std::sync::Arc<dyn crate::source_catalog::GraphSourceCatalog>,
+        catalog: std::sync::Arc<dyn lance_graph_catalog::GraphSourceCatalog>,
     ) -> Result<(
         crate::logical_plan::LogicalOperator,
         datafusion::logical_expr::LogicalPlan,
@@ -791,7 +791,7 @@ impl CypherQuery {
     /// Helper to create all plans (graph logical, DataFusion logical, physical)
     async fn create_plans(
         &self,
-        catalog: std::sync::Arc<dyn crate::source_catalog::GraphSourceCatalog>,
+        catalog: std::sync::Arc<dyn lance_graph_catalog::GraphSourceCatalog>,
         ctx: &datafusion::execution::context::SessionContext,
     ) -> Result<(
         crate::logical_plan::LogicalOperator,