fix: replace asyncio subprocess proxy with thread-based Popen proxy

asyncio subprocess PIPE unreliable for long-lived stdio bridging. Use Popen + threads instead. Also fix smoke_test.sh stdin handling.

scripts/smoke_test.sh

@@ -13,8 +13,8 @@ HEALTH_PORT="${HEALTH_PORT:-2089}"
 PASS=0
 FAIL=0
 
-ok()   { echo "  ✓ $*"; ((PASS++)); }
-fail() { echo "  ✗ $*"; ((FAIL++)); }
+ok()   { echo "  ✓ $*"; PASS=$((PASS+1)); }
+fail() { echo "  ✗ $*"; FAIL=$((FAIL+1)); }
 
 # ── Helper: send LSP initialize and read response ─────────────────────────────
 
@@ -28,8 +28,14 @@ send_lsp_init() {
 lsp_check() {
     local name="$1"
     local port="$2"
+    local timeout="${3:-3}"
     local response
-    response=$(send_lsp_init "$port" | nc -w 3 "$HOST" "$port" 2>/dev/null || true)
+    # Keep stdin open during LSP server startup: the server must NOT see EOF
+    # on stdin before it has finished responding (especially slow .NET JIT).
+    # We send the init message and then sleep for the full timeout so that nc
+    # keeps the TCP write-side open while reading the server's response.
+    response=$({ send_lsp_init "$port"; sleep "$timeout"; } \
+        | nc -w "$timeout" "$HOST" "$port" 2>/dev/null || true)
     if echo "$response" | grep -q '"result"'; then
         ok "$name LSP responded to initialize (port $port)"
     else
@@ -65,11 +71,11 @@ else
     echo "  ⚠ nc not found — skipping TCP tests"
 fi
 
-# 3. Bicep LSP
+# 3. Bicep LSP (longer timeout — .NET startup takes a few seconds)
 echo ""
 echo "Bicep LSP (TCP :$BICEP_PORT)"
 if command -v nc &>/dev/null; then
-    lsp_check "Bicep" "$BICEP_PORT"
+    lsp_check "Bicep" "$BICEP_PORT" 12
 fi
 
 # ── Summary ───────────────────────────────────────────────────────────────────