feat(algorithm): add Degree graph algorithm for vertex in/out degree …

[yourshana]

feat(algorithm): add Degree graph algorithm for vertex in/out degree computation

Closes #795

What changes were proposed in this PR?

Add a built-in UDGA Degree algorithm that computes per-vertex in-degree and out-degree. Each vertex outputs (id, in_degree, out_degree) by directly counting edges via loadEdges(EdgeDirection.IN/OUT).

No iteration or message passing is needed — degree is an intrinsic vertex property that depends only on the vertex's own edge list, not on any neighbor's state. This makes it simpler than PageRank/KCore while still exercising the full AlgorithmUserFunction interface (init/process/finish/getOutputType).

Changes:

• New Degree.java implementing AlgorithmUserFunction<Object, Object>
• Registered in BuildInSqlFunctionTable.java (UDGA section)
• Added test method testAlgorithmDegree in GQLAlgorithmTest.java
• Added test SQL gql_algorithm_degree.sql and expected result gql_algorithm_degree.txt

Isolated vertices (degree 0) are correctly output as (id, 0, 0) since loadEdges returns an empty list for vertices with no edges.

How was this PR tested?

• Tests have Added for the changes
• Production environment verified

Test testAlgorithmDegree passes using the modern_graph test graph (6 vertices, 6 edges). Expected results were manually verified:

Vertex	in_degree	out_degree
1	0	3
2	1	0
3	3	0
4	1	2
5	1	0
6	0	1

[yourshana]

#795