fix graph building logic and complete /subgraph endpoint

[pbibra]

Summary

This PR updates GraphBuilder and GraphConfig to align with the new span <> metadata configuration and moves certain post-processing logic into Astra for correctness.

GraphConfig

• Combines span tags based on a configurable delimiter to populate a metadata field.

GraphBuilder

• Generates a full list of nodes and edges when no span filter is provided.
• When a filter is present, performs an iterative DFS to remove intermediate nodes that don’t meet filter conditions.
• Filter logic is OR-based — any span satisfying at least one condition is retained in the final list of dependencies

Post-Processing within Astra
Added a post-processing DFS step during dependency generation for specific span filters. This logic was originally planned to run outside Astra, but that approach lost the span hierarchy required to properly drop intermediate spans and reconnect relevant nodes.

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

Testing

▲ ~ curl -G 'http://localhost:8081/api/v1/trace/eZVwBjNwRg6LFefMEg-nRw==/subgraph' \
    --data-urlencode 'buildFilter={"operation_name": ["dropwizard.request"]}' | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  4782  100  4782    0     0   5993      0 --:--:-- --:--:-- --:--:--  5992
{
  "subgraph": {
    "edges": [
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "437a9f05c78b14cedc3ea8f9bafae0838e0875b9dc2f4b76ba0bb36cd4c88f3f"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "cdb6c98c6b46df0b7d0e7964f80bd6b22423f2252c6264e4a89c7355055f1dab"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "7bf016d85a57cad93435953f7d833755b5248bb0dc603cc7382e9134acf628a8"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "4089069a670cc89865fe21e203382df2f13dc4f9e7289a3fbc0b4bf7a16b74d0"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "08c22953c68f7f7bcfd183f864913dffc6999b53d4f3f07471afd94e1c533230"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "2eb3447cb192a9da9cd1dd284cbcad4c4dd6f636584d17957dd7139cde08cd1a"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "f33ff1bde4908a63b85e0734beb74a5ea212cf96ac396daea4474dc004be0a7d"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "356788092a336ce0c8aa235241e877f0e65715ba0ac23084549045f63fe8fb35"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "8b91da8ba8fb5d00480270dc8735123c198f08c496e7223d43309378d2a23b79"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "e9d30c07602571ff1fe8a0b2e10cd2f117ee4256291dd638385e90e11c20a198"
      },
      {
        "metadata": {
          "operation": "dropwizard.request"
        },
        "sourceNodeId": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "targetNodeId": "c7301c3fb1c58566b2aa2bd26eaa03d2d0997232f1d666a94e1835afd9941da3"
      }
    ],
    "nodes": [
      {
        "id": "96a2b9678eb1121c7896d7153a5cb5d4ee0fecd1773173b2cbb6e0c06a2a9297",
        "metadata": {
          "resource": "//{version:(v2|v3)}/viaduct/scope/data-api{operation:(/[a-zA-Z0-9_-]+)?}",
          "service": "viaduct-dispatcher-production.viaduct-dispatcher-production"
        }
      },
      {
        "id": "cdb6c98c6b46df0b7d0e7964f80bd6b22423f2252c6264e4a89c7355055f1dab",
        "metadata": {
          "resource": "viaduct/SillaViaductSuperhostQuery",
          "service": "viaduct-shard-14-production.viaduct-production"
        }
      },
      {
        "id": "8b91da8ba8fb5d00480270dc8735123c198f08c496e7223d43309378d2a23b79",
        "metadata": {
          "resource": "viaduct/DayuMessageThreadQuery",
          "service": "viaduct-shard-180-production.viaduct-production"
        }
      },
      {
        "id": "e9d30c07602571ff1fe8a0b2e10cd2f117ee4256291dd638385e90e11c20a198",
        "metadata": {
          "resource": "viaduct/DayuMessageThreadQuery",
          "service": "viaduct-shard-8-production.viaduct-production"
        }
      },
      {
        "id": "437a9f05c78b14cedc3ea8f9bafae0838e0875b9dc2f4b76ba0bb36cd4c88f3f",
        "metadata": {
          "resource": "viaduct/PocariMediaCollectionQuery",
          "service": "viaduct-shard-15-production.viaduct-production"
        }
      },
      {
        "id": "f33ff1bde4908a63b85e0734beb74a5ea212cf96ac396daea4474dc004be0a7d",
        "metadata": {
          "resource": "viaduct/SillaViaductGuestFavoriteQuery",
          "service": "viaduct-shard-5-production.viaduct-production"
        }
      },
      {
        "id": "c7301c3fb1c58566b2aa2bd26eaa03d2d0997232f1d666a94e1835afd9941da3",
        "metadata": {
          "resource": "viaduct/PocariMediaCollectionQuery",
          "service": "viaduct-shard-13-production.viaduct-production"
        }
      },
      {
        "id": "356788092a336ce0c8aa235241e877f0e65715ba0ac23084549045f63fe8fb35",
        "metadata": {
          "resource": "viaduct/DayuGetThreadsByUserIdQuery",
          "service": "viaduct-shard-4-production.viaduct-production"
        }
      },
      {
        "id": "4089069a670cc89865fe21e203382df2f13dc4f9e7289a3fbc0b4bf7a16b74d0",
        "metadata": {
          "resource": "viaduct/DayuMessageThreadQuery",
          "service": "viaduct-shard-1-production.viaduct-production"
        }
      },
      {
        "id": "08c22953c68f7f7bcfd183f864913dffc6999b53d4f3f07471afd94e1c533230",
        "metadata": {
          "resource": "viaduct/AirlockRiskCheckQuery",
          "service": "viaduct-shard-20-production.viaduct-production"
        }
      },
      {
        "id": "2eb3447cb192a9da9cd1dd284cbcad4c4dd6f636584d17957dd7139cde08cd1a",
        "metadata": {
          "resource": "viaduct/DayuGetThreadsByUserIdQuery",
          "service": "viaduct-shard-10-production.viaduct-production"
        }
      },
      {
        "id": "7bf016d85a57cad93435953f7d833755b5248bb0dc603cc7382e9134acf628a8",
        "metadata": {
          "resource": "viaduct/SillaViaductUserPastTripsQuery",
          "service": "viaduct-shard-2-production.viaduct-production"
        }
      }
    ]
  },
  "subgraphBuildTimeMs": 31,
  "traceFetchTimeMs": 474
}
 ▲ ~ curl -G 'http://localhost:8081/api/v1/trace/eZVwBjNwRg6LFefMEg-nRw==/subgraph' \
    --data-urlencode 'buildFilter={"operation_name": ["http.request"]}' | jq
{
  "subgraph": {
    "edges": [
      {
        "metadata": {
          "operation": "http.request"
        },
        "sourceNodeId": "4089069a670cc89865fe21e203382df2f13dc4f9e7289a3fbc0b4bf7a16b74d0",
        "targetNodeId": "cc71230f648249a1ce3f4c1852a811fb9f76ce2c59f58aba602003e1a66796ec"
      },
      {
        "metadata": {
          "operation": "http.request"
        },
        "sourceNodeId": "e9d30c07602571ff1fe8a0b2e10cd2f117ee4256291dd638385e90e11c20a198",
        "targetNodeId": "af223332f46eb1260a3b5f61ee0fda386685f29505e6f2c2f537536e315f6edc"
      },
      ...
    ],
    "nodes": [
      {
        "id": "bfd1faa3abcbeec2fe2e7871474a4ca283d945fe3eb686f4819e4e14f8c85700",
        "metadata": {
          "resource": "panda/AvailabilityBatchQuery",
          "service": "panda-production.panda-production"
        }
      },
      {
        "id": "f1a283b61ca5ddf47b706990c9b5b79b0a4437e13456cb04fc91863d55ab4691",
        "metadata": {
          "resource": "/Pocari/getRichMessages",
          "service": "pocari-production.pocari-production"
        }
      },
    ...
    ]
  },
  "subgraphBuildTimeMs": 85,
  "traceFetchTimeMs": 419
}