chore(v→zig): unify API gateway + client SDK in Zig, delete V-lang trees (#66)

## Summary

Estate-wide V-lang→Zig remediation per the 2026-05-28 owner directive
(Zig is the default for APIs/FFIs/gateways/SDKs; Idris2 owns ABIs).

Removes the legacy V-lang API gateway (`v-api-gateway/`) and V client
SDK (`connectors/clients/vlang/`) and replaces them with full functional
Zig implementations:

- **`ffi/zig/`** — unified Zig gateway (REST + GraphQL proxy to Rust
core + Elixir orchestration) plus C-ABI FFI library matching the Idris2
ABI in `src/abi/Foreign.idr`. Modules: `config`, `proxy`, `router`,
`graphql`, `main`, `ffi`. Real `build.zig` replaces the previous
unsubstituted scaffold.
- **`connectors/clients/zig/`** — full Zig client SDK mirroring the V
SDK 1-to-1: `client`, `types`, `error`, `octad`, `drift`, `provenance`,
`search`, `vql`, `federation`. Includes `build.zig` + `build.zig.zon`.
- **Config + doc sweep**: ENSAID hook `v build` → `zig build`; SDK lists
in `.claude/CLAUDE.md` and `0-AI-MANIFEST.a2ml` updated; README "V API
gateway" → "unified Zig API gateway".

## Test plan

- [ ] `zig build` under `ffi/zig/` produces `verisimdb-gateway` +
`libverisimdb_ffi`
- [ ] `zig build` under `connectors/clients/zig/` exposes the
`verisimdb_client` module
- [ ] Hypatia rule `cicd_rules/vlang_detected` (in the parallel hypatia
PR) does NOT flag this repo post-merge

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.claude/CLAUDE.md

@@ -390,7 +390,7 @@ verisimdb/
 │   ├── config/
 │   └── mix.exs
 ├── connectors/                # Federation adapters + client SDKs + test infra
-│   ├── clients/               # 6 SDKs: Rust, V, Elixir, ReScript, Julia, Gleam
+│   ├── clients/               # 6 SDKs: Rust, Zig, Elixir, ReScript, Julia, Gleam
 │   ├── shared/                # JSON Schema, OpenAPI, protobuf
 │   └── test-infra/            # selur-compose: 7 databases for integration testing
 ├── container/                 # Containerfiles

.machine_readable/ENSAID_CONFIG.a2ml

@@ -2,8 +2,8 @@
 ; Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 ;
 ; ENSAID_CONFIG.a2ml — PanLL configuration for VeriSimDB.
-; VeriSimDB is a formally verified database with Idris2 ABI, Zig FFI,
-; V-lang API gateway, VQL query language, and a registry subsystem.
+; VeriSimDB is a formally verified database with Idris2 ABI, Zig FFI +
+; unified API gateway, VQL query language, and a registry subsystem.
 ; This is a key dogfooding project for the full ABI→FFI→Adapter stack.
 
 ; ─────────────────────────────────────────────────────────────────────
@@ -23,15 +23,15 @@ humidity = "dry"
 ; ─────────────────────────────────────────────────────────────────────
 [workspace]
 root = "."
-watch_extensions = [".idr", ".zig", ".v", ".vql", ".gleam", ".toml"]
-; .idr = ABI definitions, .zig = FFI bridge, .v = API gateway,
+watch_extensions = [".idr", ".zig", ".vql", ".gleam", ".toml"]
+; .idr = ABI definitions, .zig = FFI bridge + API gateway,
 ; .vql = VeriSimDB Query Language, .gleam = REPL/tooling
 ignore_patterns = ["build/", ".git/", "zig-cache/", "zig-out/", "_build/"]
 editor = "vscodium"
 build_command = "just build"
 test_command = "just test"
 language_id = "idris2"
-; Primary specification language. Implementation spans Zig + V + Gleam.
+; Primary specification language. Implementation spans Zig + Gleam.
 
 ; ─────────────────────────────────────────────────────────────────────
 ; [preferences] — developer preferences and UI settings
@@ -52,7 +52,7 @@ panel_layout = "three-column"
 enabled = [
   "valence-shell",       ; Terminal + command execution
   "editor-bridge",       ; Editor integration
-  "build-dashboard",     ; Multi-language build status (Idris2 + Zig + V)
+  "build-dashboard",     ; Multi-language build status (Idris2 + Zig + Gleam)
   "boj",                 ; BoJ dashboard — VeriSimDB is a BoJ consumer
   "database",            ; Database inspection — dogfooding VeriSimDB itself
   "vm-inspector",        ; Query engine / VQL inspection
@@ -64,7 +64,7 @@ enabled = [
 ]
 
 disabled = [
-  "network",             ; Network handled by V-lang adapter
+  "network",             ; Network handled by Zig gateway
   "container",           ; Container builds handled externally
   "fleet",               ; Single-repo work
 ]
@@ -81,12 +81,12 @@ action = "run_command"
 command = "cd ffi/zig && zig build test"
 description = "Rebuild and test Zig FFI when Idris2 ABI definitions change"
 
-[workflows.adapter-on-ffi-change]
+[workflows.gateway-on-ffi-change]
 trigger = "file_save"
 match = "ffi/zig/src/*.zig"
 action = "run_command"
-command = "cd v-api-gateway && v build ."
-description = "Rebuild V-lang API gateway when Zig FFI changes"
+command = "cd ffi/zig && zig build"
+description = "Rebuild unified Zig gateway + FFI when sources change"
 
 [workflows.vql-test-on-save]
 trigger = "file_save"

0-AI-MANIFEST.a2ml

@@ -70,7 +70,7 @@
       (description "Federation adapters (10) and client SDKs (6)")
       (location "connectors/")
       (adapters "MongoDB" "Redis" "DuckDB" "ClickHouse" "SurrealDB" "SQLite" "Neo4j" "VectorDB" "InfluxDB" "ObjectStorage")
-      (sdks "Rust" "V" "Elixir" "ReScript" "Julia" "Gleam")))
+      (sdks "Rust" "Zig" "Elixir" "ReScript" "Julia" "Gleam")))
 
   (critical-invariants
     (rule "SCM files ONLY in .machine_readable/ — never root")

README.adoc

@@ -389,7 +389,7 @@ curl -X POST http://localhost:8080/api/v1/normalizer/trigger/entity-001
 
 === gRPC (port 50051)
 
-VeriSimDB's gRPC server runs directly on the Rust core (via tonic) on port 50051. The V API gateway does not proxy gRPC traffic — connect directly to the Rust core.
+VeriSimDB's gRPC server runs directly on the Rust core (via tonic) on port 50051. The unified Zig API gateway does not proxy gRPC traffic — connect directly to the Rust core.
 
 [source,bash]
 ----