fix: Support Returning Edge Properties Immediately After Edge Creation

[liulx20]

This pull request refactors the edge insertion API throughout the codebase to return additional information when adding edges. Instead of returning only a status or offset, the relevant AddEdge and put_edge methods now return a pair containing the previous offset and a pointer to the edge data. This change provides more context to the caller and enables more advanced use cases, such as direct access to the newly inserted edge's data.

[zhanglei1949]

Is there any better choice to wrap the returned edge, rather than returning a implementation-specific void* pointer?

[Copilot]

Pull request overview

This PR refactors the edge insertion path so that AddEdge/put_edge can return a reference to the newly inserted edge’s payload, enabling Cypher CREATE ... RETURN e.<prop> to surface edge properties immediately after creation.

Changes:

• Change AddEdge return types across storage/transaction layers to return an edge-data pointer/handle (and, internally, a {offset, ptr} pair).
• Plumb the returned edge payload pointer into execution (CreateEdge) so returned edge columns carry property access data.
• Add a Python binding test asserting RETURN e.since works immediately after CREATE.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tools/python_bind/tests/test_db_query.py	Adds coverage for returning an edge property immediately after edge creation.
src/transaction/update_transaction.cc	Updates update-transaction edge insertion to return the inserted edge payload pointer.
src/transaction/insert_transaction.cc	Updates insert-transaction edge insertion API to return a pointer-like success indicator.
src/storages/graph/property_graph.cc	Changes PropertyGraph::AddEdge to return {offset, data_ptr} from the underlying edge table.
src/storages/graph/graph_interface.cc	Updates AP update interface AddEdge to return the inserted edge payload pointer.
src/storages/graph/edge_table.cc	Propagates CSR put_generic_edge return pair and returns {oe_offset, data_ptr}.
src/execution/common/operators/insert/create_edge.cc	Stores returned edge payload pointer into edge columns so edge property accessors can read it.
include/neug/transaction/update_transaction.h	Updates update transaction and TP update interface AddEdge signatures to return const void*.
include/neug/transaction/insert_transaction.h	Updates insert transaction and TP insert interface AddEdge signatures/docs to return const void*.
include/neug/storages/graph/property_graph.h	Updates PropertyGraph::AddEdge signature to return std::pair<int32_t, const void*>.
include/neug/storages/graph/graph_interface.h	Updates StorageInsertInterface/StorageUpdateInterface AddEdge return types and documentation.
include/neug/storages/graph/edge_table.h	Updates EdgeTable::AddEdge signature to return {offset, data_ptr}.
include/neug/storages/csr/mutable_csr.h	Updates CSR put_edge implementations to return {prev_size, data_ptr}.
include/neug/storages/csr/csr_base.h	Updates CSR base virtuals to return {offset, data_ptr} pairs.

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[zhanglei1949]

should be MANT_TO_MANY

[zhanglei1949]

LGTM