fix(docs): correct storage-backends adapter names, kwargs, and inventory

The adapter inventory and connection examples referenced classes that
don't exist in semantica.graph_store (Neo4jGraphStore, NeptuneGraphStore,
AgeGraphStore) and used constructor kwargs that don't match the actual
adapters (username vs user, host vs endpoint, url vs endpoint, etc.),
verified against each adapter's real __init__ signature and by
constructing every example against the live classes.

- Correct class names: Neo4jStore, AmazonNeptuneStore, ApacheAgeStore
- Fix kwargs for all seven examples to match actual constructors
- Fix ApacheAgeStore's connection_string to libpq keyword=value format
  instead of a postgresql:// DSN, which the adapter doesn't accept
- Reclassify Anzo from interface/BYO to built-in — AnzoStore is a real,
  exported, tested adapter
- Add the two adapters missing from the inventory: FalkorDBStore and
  OxigraphStore
- Replace the literal password='password' example with an env var
- Note a real RDF4JStore bug found while verifying the RDF4J example:
  repository_id is a named constructor parameter but the implementation
  reads it from **config instead, so it's silently ignored and the
  store always connects to the "default" repository

docs/storage-backends.md

@@ -15,13 +15,15 @@ This page is intentionally conservative: it distinguishes between an adapter exi
 
 | Backend | Model | Adapter | Status | Reference |
 | --- | --- | --- | --- | --- |
-| Neo4j | LPG | `semantica.graph_store.Neo4jGraphStore` | built-in | `cookbook/introduction/09_Graph_Store.ipynb` |
-| Amazon Neptune | LPG | `semantica.graph_store.NeptuneGraphStore` | built-in | `cookbook/introduction/21_Amazon_Neptune_Store.ipynb` |
-| Apache AGE | LPG | `semantica.graph_store.AgeGraphStore` | built-in | `docs/graph_stores/apache_age.md` |
+| Neo4j | LPG | `semantica.graph_store.Neo4jStore` | built-in | `cookbook/introduction/09_Graph_Store.ipynb` |
+| FalkorDB | LPG | `semantica.graph_store.FalkorDBStore` | built-in | `docs/reference/graph_store.md` |
+| Amazon Neptune | LPG | `semantica.graph_store.AmazonNeptuneStore` | built-in | `cookbook/introduction/21_Amazon_Neptune_Store.ipynb` |
+| Apache AGE | LPG | `semantica.graph_store.ApacheAgeStore` | built-in | `docs/graph_stores/apache_age.md` |
 | RDF4J | RDF | `semantica.triplet_store.RDF4JStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` |
 | Apache Jena | RDF | `semantica.triplet_store.JenaStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` |
 | Blazegraph | RDF | `semantica.triplet_store.BlazegraphStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` |
-| Anzo | RDF | `semantica.triplet_store.AnzoStore` | interface/BYO | `cookbook/introduction/20_Triplet_Store.ipynb` |
+| Anzo | RDF | `semantica.triplet_store.AnzoStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` |
+| Oxigraph | RDF | `semantica.triplet_store.OxigraphStore` | built-in | `docs/reference/triplet_store.md` |
 
 ## Feature matrix
 
@@ -30,12 +32,14 @@ This page is intentionally conservative: it distinguishes between an adapter exi
 | Backend | Model | Ingestion | Context graph construction | Reasoning/analytics | Provenance | Known limitations |
 | --- | --- | --- | --- | --- | --- | --- |
 | Neo4j | LPG | Yes | Yes | Yes | Partial | Provenance and context metadata are stored as node and edge properties; relationship properties and stable node identifiers are required. |
+| FalkorDB | LPG | Yes | Yes | Partial | Partial | Redis-based; provenance depends on node/edge properties, and multi-graph isolation depends on the selected graph name. |
 | Amazon Neptune | LPG | Yes | Yes | Partial | Partial | Use the property-graph endpoint; AWS auth, VPC, and endpoint configuration can affect local tests. Provenance depends on node/edge properties. |
 | Apache AGE | LPG | Yes | Yes | Partial | Partial | Runs through PostgreSQL/AGE; Cypher compatibility and property handling can differ from standalone LPG engines. |
-| RDF4J | RDF | Yes | Partial | Partial | Partial | Context separation relies on named graphs; triple-level provenance may require reification or graph-level metadata. |
+| RDF4J | RDF | Yes | Partial | Partial | Partial | Context separation relies on named graphs; triple-level provenance may require reification or graph-level metadata. `RDF4JStore(repository_id=...)` currently has no effect — the constructor always connects to the `"default"` repository regardless of the value passed; track a fix separately. |
 | Apache Jena | RDF | Yes | Partial | Partial | Partial | Named graphs are needed for context separation; backend configuration and transaction behavior matter. |
 | Blazegraph | RDF | Yes | Partial | Partial | Partial | Use quads/named graphs for context; IRI stability and graph naming matter for provenance. |
-| Anzo | RDF | BYO | BYO | BYO | BYO | Anzo deployments are environment-specific; validate repository/graph naming, named-graph support, and provenance mapping. |
+| Anzo | RDF | Yes | Partial | Partial | Partial | Anzo deployments are environment-specific; validate `dataset_uri`/graphmart naming, named-graph support, and provenance mapping. |
+| Oxigraph | RDF | Yes | Partial | Partial | Partial | Embedded, single-process store (in-memory or on-disk); named graphs are supported, but there is no separate server process to scale independently. |
 
 ## RDF and LPG differences
 
@@ -51,34 +55,48 @@ Prefer the referenced notebook cells for a working setup. The examples below sho
 ### Neo4j
 
 ```python
-from semantica.graph_store import Neo4jGraphStore
+import os
+from semantica.graph_store import Neo4jStore
 
-store = Neo4jGraphStore(
+store = Neo4jStore(
     uri='bolt://localhost:7687',
-    username='neo4j',
-    password='password'
+    user='neo4j',
+    password=os.environ['NEO4J_PASSWORD']
+)
+```
+
+### FalkorDB
+
+```python
+from semantica.graph_store import FalkorDBStore
+
+store = FalkorDBStore(
+    host='localhost',
+    port=6379,
+    graph_name='semantica'
 )
 ```
 
 ### Amazon Neptune
 
 ```python
-from semantica.graph_store import NeptuneGraphStore
+from semantica.graph_store import AmazonNeptuneStore
 
-store = NeptuneGraphStore(
-    host='your-neptune-endpoint',
-    port=8182
+store = AmazonNeptuneStore(
+    endpoint='your-neptune-cluster-endpoint',
+    port=8182,
+    region='us-east-1'
 )
 ```
 
 ### Apache AGE
 
 ```python
-from semantica.graph_store import AgeGraphStore
+from semantica.graph_store import ApacheAgeStore
 
-store = AgeGraphStore(
-    dsn='postgresql://user:password@localhost:5432/semantica',
-    graph='semantica'
+store = ApacheAgeStore(
+    connection_string='host=localhost dbname=agedb user=postgres password=postgres',
+    graph_name='semantica'
 )
 ```
 
@@ -88,8 +106,8 @@ store = AgeGraphStore(
 from semantica.triplet_store import RDF4JStore
 
 store = RDF4JStore(
-    url='http://localhost:8080/rdf4j-server',
-    repository='semantica'
+    endpoint='http://localhost:8080/rdf4j-server',
+    repository_id='semantica'  # currently has no effect; connects to "default" (see Known limitations)
 )
 ```
 
@@ -99,8 +117,7 @@ store = RDF4JStore(
 from semantica.triplet_store import JenaStore
 
 store = JenaStore(
-    url='http://localhost:3030',
-    dataset='semantica'
+    endpoint='http://localhost:3030/ds'
 )
 ```
 
@@ -110,7 +127,7 @@ store = JenaStore(
 from semantica.triplet_store import BlazegraphStore
 
 store = BlazegraphStore(
-    url='http://localhost:9999/blazegraph/sparql'
+    endpoint='http://localhost:9999/blazegraph/sparql'
 )
 ```
 
@@ -120,9 +137,18 @@ store = BlazegraphStore(
 from semantica.triplet_store import AnzoStore
 
 store = AnzoStore(
-    url='http://anzo-host:10000',
-    repository='semantica'
+    endpoint='http://anzo-host:8080',
+    dataset_uri='http://cambridgesemantics.com/Graphmart/your-graphmart-id'
 )
 ```
 
+### Oxigraph
+
+```python
+from semantica.triplet_store import OxigraphStore
+
+# Omit `path` for an in-memory store; pass a directory for on-disk persistence.
+store = OxigraphStore(path='./semantica-oxigraph-data')
+```
+
 Replace hostnames, ports, repositories, graphs, and credentials with values from your environment. For regulated or self-hosted deployments, keep credentials in environment variables or secret storage rather than source code.