docs(changelog): add provenance upstream traversal fix entry (#480, #470)

Co-authored-by: Sameer6305 <sameer6305@users.noreply.github.com>
Co-authored-by: KaifAhmad1 <mohammadk78600@gmail.com>

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- **Fix: Provenance traversal now includes multi-hop upstream ancestors + edge direction classification** (closes #470, PR #480 by @Sameer6305, review fixes by @KaifAhmad1):
+  - **Bug — upstream ancestors silently excluded**: `_build_provenance()` built a directed `nx.DiGraph` and seeded first-hop neighbors correctly, but the final subgraph extraction called `nx.ego_graph(..., undirected=False)`. With directed traversal, ego-graph expansion only follows outgoing edges from the focus node, so any node that *points into* the focus node (i.e. an upstream ancestor at depth ≥ 2) was invisible. For the chain `Source → Intermediate → node_id`, `Intermediate` appeared at hop 1 but `Source` was silently dropped. Fixed by changing to `undirected=True` — the radius expansion now traverses both incoming and outgoing edges while the underlying `DiGraph` is preserved, so edge source/target semantics remain correct.
+  - **Enhancement — edge direction classification**: `ProvenanceEdge` gains a `direction: str` field. Each edge in the provenance subgraph is classified relative to the focus node: `"upstream"` when `target == node_id` (edge flows into the focus node), `"downstream"` when `source == node_id` (edge flows out), and `"lateral"` for all other edges between non-focus neighbors. This lets consumers distinguish ancestor provenance from descendant impact without re-traversing the graph.
+  - **Enhancement — grouped markdown report**: `_render_markdown()` now groups lineage edges under separate `## Upstream`, `## Downstream`, and `## Lateral` sections instead of a flat `## Lineage Edges` list. Empty sections are omitted. This improves readability of exported provenance reports.
+  - **Schema consolidation**: `ProvenanceNode`, `ProvenanceEdge`, and `ProvenanceResponse` moved from inline definitions in `routes/provenance.py` to the shared `semantica/explorer/schemas.py`, matching the convention used by all other Explorer routes. `ProvenanceNode.parent_id` is now `Optional[str] = None`.
+  - **Merge conflicts resolved**: Resolved all conflict markers in `provenance.py`, `app.py`, and `.gitignore`; restored the complete router import set in `app.py` (`graph`, `sparql`, `temporal`, `vocabulary`) that the conflict had dropped.
+  - 2 new tests in `tests/explorer/test_provenance_route.py`: `test_build_provenance_direction_classification_chain` (asserts `Source` and `Intermediate` both appear for `Source → Intermediate → node_id`; verifies `Intermediate → node_id` classified as `"upstream"`) and `test_render_markdown_groups_edges_by_direction` (asserts grouped section headings and correct edge lines in output).
+
 - **Fix: `OWLExporter._export_owl_turtle` invalid Turtle syntax and silent data-property omission** (closes #478 by @KaifAhmad1):
   - **Bug 1 — Invalid Turtle syntax**: `_export_owl_turtle` unconditionally wrote `rdfs:label` with a closing period (`.`), then appended `rdfs:subClassOf`, `rdfs:domain`, and `rdfs:range` triples after the closed block. Any RDF parser would reject the output. Fixed by introducing `_ttl_block(subject_uri, rdf_type, predicates)` — all predicate-object pairs for a subject are accumulated first, then joined with ` ;\n    ` and terminated with a single ` .`, producing valid Turtle in all cases.
   - **Bug 2 — Data properties silently dropped**: `_export_owl_turtle` had loops for `classes` and `object_properties` but no loop for `data_properties`, so all `owl:DatatypeProperty` declarations were silently omitted. Added the missing loop, mirroring the existing object-property loop.