# Signals Callgraph Ingestion with Content-Addressed Storage

## Module
Signals

## Status
VERIFIED

## Description
Callgraph normalization pipeline accepting Java/Node/Python/Go call-graph formats, normalizing to canonical symbol representation, and storing with content-addressed identifiers for deterministic replay.

## Implementation Details
- **Modules**: `src/Signals/StellaOps.Signals/Services/`, `src/Signals/StellaOps.Signals/Parsing/`, `src/Signals/StellaOps.Signals/Models/`
- **Key Classes**:
  - `CallgraphIngestionService` (`src/Signals/StellaOps.Signals/Services/CallgraphIngestionService.cs`) - ingests call graphs from multiple language formats and normalizes to canonical representation
  - `CallgraphParserResolver` (`src/Signals/StellaOps.Signals/Parsing/ICallgraphParserResolver.cs`) - resolves language-specific parsers (Java, Node, Python, Go)
  - `CallgraphIngestRequest` (`src/Signals/StellaOps.Signals/Models/CallgraphIngestRequest.cs`) - ingest request model
  - `CallgraphIngestResponse` (`src/Signals/StellaOps.Signals/Models/CallgraphIngestResponse.cs`) - ingest response with content-addressed IDs
  - `CallgraphManifest` (`src/Signals/StellaOps.Signals/Models/CallgraphManifest.cs`) - manifest tracking ingested call-graph documents
  - `CallgraphSchemaVersions` (`src/Signals/StellaOps.Signals/Models/CallgraphSchemaVersions.cs`) - schema version constants for call-graph formats
- **Interfaces**: `ICallgraphIngestionService`, `ICallgraphParserResolver`
- **Source**: SPRINT_0143_0001_0001_signals.md

## E2E Test Plan
- [ ] Ingest a Java call graph and verify it is normalized to canonical symbol representation
- [ ] Ingest call graphs for Node, Python, and Go and verify language-specific parsing
- [ ] Verify content-addressed storage: ingest the same call graph twice and confirm the same content ID is returned
- [ ] Verify deterministic replay: retrieve a stored call graph by content ID and confirm it matches the original
- [ ] Verify schema version handling: ingest call graphs with different schema versions

## Verification
- **Run ID**: run-001
- **Date**: 2026-02-12
- **Result**: PASS (Tier 0 + Tier 1 + Tier 2d)
- **Tests**: CallgraphIngestionServiceTests (1 test) - ingestion, normalization, CAS storage, graph hash, manifest