feat(v-lang): add 4 V-lang connectors — Phase 2 remaining (graphdb, objectstore, ldap, vpn)

Complete the proven-servers Phase 2 connector set with four new
V-Ecosystem API interface modules:

- v-graphdb: Multi-dialect graph database client (Neo4j Bolt/Cypher,
  TinkerPop Gremlin, W3C SPARQL) with node/edge CRUD and transactions
- v-objectstore: S3-compatible object storage client (AWS S3, MinIO,
  Ceph RADOS) with bucket ops, multipart upload, presigned URLs, and
  AWS Signature V4 request signing
- v-ldap: LDAPv3 (RFC 4511) directory service client with BER-TLV
  encoding, bind/unbind (simple + SASL), search, add/modify/delete,
  compare, and modify DN
- v-vpn: VPN management client (WireGuard userspace API + OpenVPN
  management socket) with peer lifecycle, key generation, tunnel
  configuration, and status monitoring

Each connector follows the established pattern: V source module,
Idris2 ABI type definitions, contractiles Trustfile, and README.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

v-ecosystem/v-api-interfaces/v-graphdb/README.adoc

@@ -0,0 +1,14 @@
+= v-graphdb
+// SPDX-License-Identifier: PMPL-1.0-or-later
+
+Multi-dialect graph database protocol connector for the V-Ecosystem API interfaces layer.
+Supports Neo4j Bolt (Cypher), Apache TinkerPop (Gremlin), and W3C SPARQL endpoints through a unified client interface.
+Provides node/edge CRUD, parameterised query execution, and explicit transaction management.
+
+== Author
+
+Jonathan D.A. Jewell
+
+== Source
+
+`src/graphdb.v`

v-ecosystem/v-api-interfaces/v-graphdb/contractiles/Trustfile.a2ml

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+# Trustfile.a2ml -- v-graphdb
+# SPDX-License-Identifier: PMPL-1.0-or-later
+# Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
+#
+# Contractile trust specification for the v-graphdb protocol module.
+# Evaluated by the contractile-cli (must/trust/dust/intend/k9) toolchain.
+
+[trust]
+post-quantum-keys = "pending"
+threat-model = "network-facing-query-engine"
+formal-verification = "idris2-abi"
+audit-status = "unaudited"
+
+[must]
+invariant-checks = ["input-validation", "query-parameterisation", "connection-lifecycle", "transaction-state-machine", "property-escaping"]
+build-contract = "v build src/"
+
+[dust]
+recovery = "rollback-and-reconnect"
+rollback = "abort-transaction-close-connection"

v-ecosystem/v-api-interfaces/v-graphdb/src/abi/Types.idr

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+-- SPDX-License-Identifier: PMPL-1.0-or-later
+-- Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath)
+--
+-- Idris2 ABI type definitions for the v-graphdb protocol.
+-- Graph database query dialects, node/edge types, transaction states,
+-- and result set structures.
+
+module Types
+
+import Data.List
+
+||| Graph query dialect supported by the connector.
+public export
+data QueryDialect : Type where
+  Cypher  : QueryDialect  -- Neo4j Cypher Query Language
+  Gremlin : QueryDialect  -- Apache TinkerPop traversal language
+  SPARQL  : QueryDialect  -- W3C SPARQL 1.1 query/update
+
+||| Connection lifecycle state for graph database sessions.
+public export
+data ConnState : Type where
+  Disconnected : ConnState
+  Connecting   : ConnState
+  Connected    : ConnState
+  InTransaction : ConnState
+
+||| Transaction lifecycle state.
+public export
+data TxState : Type where
+  TxNone       : TxState  -- No transaction active
+  TxActive     : TxState  -- Transaction in progress
+  TxCommitted  : TxState  -- Successfully committed
+  TxRolledBack : TxState  -- Rolled back (explicitly or on error)
+
+||| A labelled vertex in the property graph.
+public export
+record Node where
+  constructor MkNode
+  nodeId     : String
+  labels     : List String
+  properties : List (String, String)
+
+||| A directed, typed relationship between two nodes.
+public export
+record Edge where
+  constructor MkEdge
+  edgeId     : String
+  relType    : String
+  sourceId   : String
+  targetId   : String
+  properties : List (String, String)
+
+||| A single column in a query result set.
+public export
+record Column where
+  constructor MkColumn
+  name  : String
+  index : Nat
+
+||| A row of string-valued cells in a query result set.
+public export
+record Row where
+  constructor MkRow
+  cells : List (String, String)
+
+||| Complete result set returned by a graph query.
+public export
+record QueryResult where
+  constructor MkQueryResult
+  columns : List Column
+  rows    : List Row
+  count   : Nat