feat: add proc_open fallback driver for zero-dependency PHP usage

ext-ffi is no longer required — moved to `suggest` in composer.json.
When FFI is unavailable, the wrapper automatically spawns `anvildb-server`
(a new Rust binary) and communicates via JSON-over-stdin/stdout pipes.

- Add DriverInterface, FFIDriver, ProcessDriver, DriverFactory abstraction
- Add anvildb-server binary (core/src/bin/server.rs) with full command set
- Refactor AnvilDb, Collection, QueryBuilder from \FFI\CData to DriverInterface
- Update release.yml to package anvildb-server alongside the shared library
- Update docs: architecture, ci-cd, wrapper-development, READMEs

Both drivers pass all 22 PHP tests and 50 Rust tests.
Override with ANVILDB_DRIVER=ffi|process or ANVILDB_BIN_PATH env vars.

Author: Kevinsillo

.gitattributes

@@ -26,3 +26,5 @@ CONTRIBUTING.md      export-ignore
 *.so    binary
 *.dylib binary
 *.dll   binary
+anvildb-server     binary
+anvildb-server.exe binary

.github/workflows/release.yml

@@ -64,6 +64,7 @@ jobs:
         run: |
           mkdir -p dist/${{ matrix.dir }}
           cp target/${{ matrix.target }}/release/${{ matrix.artifact }} dist/${{ matrix.dir }}/
+          cp target/${{ matrix.target }}/release/anvildb-server dist/${{ matrix.dir }}/
           tar -czf anvildb-${{ matrix.dir }}.tar.gz -C dist ${{ matrix.dir }}
 
       - name: Package artifact (Windows)
@@ -72,6 +73,7 @@ jobs:
         run: |
           mkdir -p dist/${{ matrix.dir }}
           cp target/${{ matrix.target }}/release/${{ matrix.artifact }} dist/${{ matrix.dir }}/
+          cp target/${{ matrix.target }}/release/anvildb-server.exe dist/${{ matrix.dir }}/
           tar -czf anvildb-${{ matrix.dir }}.tar.gz -C dist ${{ matrix.dir }}
 
       - name: Upload artifact

README.md

@@ -40,7 +40,7 @@ The goal was to have something fast for scaffolding projects and prototyping ide
 
 ## Wrappers
 
-The core exposes a C API (`anvildb.h`) — any language with FFI support can integrate.
+The core exposes a C API (`anvildb.h`) and a JSON-over-pipes protocol (`anvildb-server`) — any language can integrate via FFI or subprocess.
 
 | Language | Package | Status |
 |----------|---------|--------|
@@ -55,9 +55,11 @@ Application
     |
     v
 Language Wrapper (PHP, Python, etc.)
-    | JSON strings + opaque handle
-    v
-Rust Core Engine (libanvildb.so)
+    |                          |
+    | FFI (direct, fastest)    | Process (no extensions needed)
+    | JSON strings + handle    | JSON lines over stdin/stdout
+    v                          v
+Rust Core Engine           anvildb-server
     |  - Write Buffer (dirty tracking + batched flush)
     |  - LRU Cache (auto-invalidated)
     |  - In-memory Indexes (Hash / Unique / Range)

core/Cargo.toml

@@ -8,6 +8,10 @@ description = "Core engine for AnvilDB — high-performance JSON file-based stor
 name = "anvildb"
 crate-type = ["cdylib", "rlib"]
 
+[[bin]]
+name = "anvildb-server"
+path = "src/bin/server.rs"
+
 [features]
 default = []
 debug-logs = ["env_logger"]