fix: coprocessor segfault — replace filesystem probing with env-only detection

The coprocessor init was segfaulting because std.fs.openFileAbsolute
and std.posix.getenv don't work safely from a Zig static library
linked into the V runtime. Replaced with C extern getenv() and
env-only device detection.

Also downgraded Grade to B-RC (honest assessment: Grade A requires
real external users and community adoption, not just code).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: hyperpolymath

.machine_readable/STATE.a2ml

@@ -8,16 +8,16 @@ project = "boj-server"
 version = "0.2.0"
 last-updated = "2026-03-09"
 status = "active"
-grade = "A-production"
+grade = "B-rc"
 
 [project-context]
 name = "Bundle of Joy Server"
 purpose = "Unified server capability catalogue solving the combinatoric explosion of developer server protocols. Provides a 2D matrix of formally verified cartridges (protocol types x capability domains), distributed via community-hosted nodes with hash attestation and gossip protocol."
 completion-percentage = 100
 
 [position]
-phase = "production"
-maturity = "production"
+phase = "rc"
+maturity = "release-candidate"
 
 [route-to-mvp]
 milestones = [

TOPOLOGY.md

@@ -189,7 +189,7 @@ Feedback   │  ██  │      │      │      │      │       │      
 
 ## Honest Assessment (2026-03-09)
 
-**Overall: Grade A Production — All Grade B→A items complete**
+**Overall: Grade B RC — Code complete, needs external validation for Grade A**
 
 What is genuinely done:
 - 18 cartridges with ABI+FFI+Adapter structure (3 at Grade C, 15 at Grade D)

ffi/zig/build.zig

@@ -149,6 +149,7 @@ pub fn build(b: *std.Build) void {
         .root_source_file = b.path("src/coprocessor.zig"),
         .target = target,
         .optimize = optimize,
+        .link_libc = true,
     });
 
     const coprocessor_lib = b.addLibrary(.{

ffi/zig/src/coprocessor.zig

@@ -20,6 +20,8 @@
 
 const std = @import("std");
 
+extern fn getenv(name: [*:0]const u8) ?[*:0]const u8;
+
 // ═══════════════════════════════════════════════════════════════════════
 // Constants
 // ═══════════════════════════════════════════════════════════════════════
@@ -102,101 +104,30 @@ var initialised: bool = false;
 // Detection
 // ═══════════════════════════════════════════════════════════════════════
 
-/// Detect CUDA devices by checking for /dev/nvidia* or CUDA_VISIBLE_DEVICES env.
-fn detectCuda() void {
-    // Check environment override first
-    if (std.posix.getenv("BOJ_CUDA_DEVICES")) |val| {
-        const count = std.fmt.parseInt(u8, val, 10) catch 0;
-        var i: u8 = 0;
-        while (i < count and device_count < MAX_DEVICES) : (i += 1) {
-            var dev = &devices[device_count];
-            dev.kind = .cuda;
-            dev.status = .available;
-            dev.device_index = i;
-            const label = "CUDA Device";
-            @memcpy(dev.name[0..label.len], label);
-            dev.name_len = label.len;
-            device_count += 1;
-        }
-        return;
-    }
-    // Probe /dev/nvidia0
-    if (std.fs.openFileAbsolute("/dev/nvidia0", .{})) |f| {
-        f.close();
-        var dev = &devices[device_count];
-        dev.kind = .cuda;
-        dev.status = .available;
-        dev.device_index = 0;
-        const label = "NVIDIA GPU";
-        @memcpy(dev.name[0..label.len], label);
-        dev.name_len = label.len;
-        device_count += 1;
-    } else |_| {}
-}
-
-/// Detect ROCm devices by checking for /dev/kfd (AMD kernel fusion driver).
-fn detectRocm() void {
-    if (std.posix.getenv("BOJ_ROCM_DEVICES")) |val| {
-        const count = std.fmt.parseInt(u8, val, 10) catch 0;
-        var i: u8 = 0;
-        while (i < count and device_count < MAX_DEVICES) : (i += 1) {
-            var dev = &devices[device_count];
-            dev.kind = .rocm;
-            dev.status = .available;
-            dev.device_index = i;
-            const label = "ROCm Device";
-            @memcpy(dev.name[0..label.len], label);
-            dev.name_len = label.len;
-            device_count += 1;
+/// Detect accelerator devices from environment variables.
+/// Uses env-only detection (no filesystem probing) for safe cross-runtime use.
+/// Set BOJ_CUDA_DEVICES=N, BOJ_ROCM_DEVICES=N, etc. to declare devices.
+fn detectFromEnv(env_name: [*:0]const u8, kind: AcceleratorKind, label: []const u8) void {
+    const val = getenv(env_name) orelse return;
+    // Parse the C string to get count
+    var count: u8 = 0;
+    var i: usize = 0;
+    while (val[i] != 0 and i < 3) : (i += 1) {
+        if (val[i] >= '0' and val[i] <= '9') {
+            count = count * 10 + (val[i] - '0');
         }
-        return;
     }
-    if (std.fs.openFileAbsolute("/dev/kfd", .{})) |f| {
-        f.close();
+    if (count == 0) return;
+    var dev_idx: u8 = 0;
+    while (dev_idx < count and device_count < MAX_DEVICES) : (dev_idx += 1) {
         var dev = &devices[device_count];
-        dev.kind = .rocm;
+        dev.kind = kind;
         dev.status = .available;
-        dev.device_index = 0;
-        const label = "AMD GPU";
-        @memcpy(dev.name[0..label.len], label);
-        dev.name_len = label.len;
+        dev.device_index = dev_idx;
+        const actual_len = @min(label.len, MAX_NAME_LEN);
+        @memcpy(dev.name[0..actual_len], label[0..actual_len]);
+        dev.name_len = actual_len;
         device_count += 1;
-    } else |_| {}
-}
-
-/// Detect TPU via BOJ_TPU_DEVICES environment variable.
-fn detectTpu() void {
-    if (std.posix.getenv("BOJ_TPU_DEVICES")) |val| {
-        const count = std.fmt.parseInt(u8, val, 10) catch 0;
-        var i: u8 = 0;
-        while (i < count and device_count < MAX_DEVICES) : (i += 1) {
-            var dev = &devices[device_count];
-            dev.kind = .tpu;
-            dev.status = .available;
-            dev.device_index = i;
-            const label = "TPU Device";
-            @memcpy(dev.name[0..label.len], label);
-            dev.name_len = label.len;
-            device_count += 1;
-        }
-    }
-}
-
-/// Detect FPGA via BOJ_FPGA_DEVICES environment variable.
-fn detectFpga() void {
-    if (std.posix.getenv("BOJ_FPGA_DEVICES")) |val| {
-        const count = std.fmt.parseInt(u8, val, 10) catch 0;
-        var i: u8 = 0;
-        while (i < count and device_count < MAX_DEVICES) : (i += 1) {
-            var dev = &devices[device_count];
-            dev.kind = .fpga;
-            dev.status = .available;
-            dev.device_index = i;
-            const label = "FPGA Device";
-            @memcpy(dev.name[0..label.len], label);
-            dev.name_len = label.len;
-            device_count += 1;
-        }
     }
 }
 
@@ -219,11 +150,11 @@ fn init() void {
     cpu_dev.name_len = cpu_label.len;
     device_count = 1;
 
-    // Detect accelerators
-    detectCuda();
-    detectRocm();
-    detectTpu();
-    detectFpga();
+    // Detect accelerators from environment variables
+    detectFromEnv("BOJ_CUDA_DEVICES", .cuda, "CUDA Device");
+    detectFromEnv("BOJ_ROCM_DEVICES", .rocm, "ROCm Device");
+    detectFromEnv("BOJ_TPU_DEVICES", .tpu, "TPU Device");
+    detectFromEnv("BOJ_FPGA_DEVICES", .fpga, "FPGA Device");
 
     initialised = true;
 }