Initial commit: Transcience MVP

Top-down twin-stick bullet-hell, Godot 4.7, server-authoritative dedicated
server with client-side prediction. Clients send input only; the server
resolves every hit for both players and enemies (no PvP).

- SimWorld: whole simulation as plain RefCounted objects (no nodes, no
  physics server), ~0.24ms/tick at peak load -- runs headless for free and
  drives 78 tests in under a second
- BulletPool: struct-of-arrays bullet storage, replicated as spawn/despawn
  events rather than per-tick state
- Emitter framework (Ring/AimedSpread/WallGap/ArcSweep) shared by trash
  enemies and bosses -- a new boss is data in src/content/content.gd, no
  simulation changes
- The Warden of the Fold: stationary 4-phase boss built entirely on that
  format
- Lobby hub with a portal into on-demand dungeon instances; one process
  hosts the hub plus every concurrent dungeon
- Emergency escape: 3s server-owned channel, cancelled by damage
- tools/check.sh, test.sh (GUT), smoke.sh (real server + bot clients over
  ENet), bench.gd; git hooks wired to the same scripts
- docs/ARCHITECTURE.md, NETCODE.md, WORKFLOW.md, ROADMAP.md

tools/smoke.sh

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+# End-to-end integration test: boot a dedicated server, connect two scripted
+# bot clients over a real ENet socket, and assert that the whole loop happened --
+# handshake, lobby, portal into a dungeon, and the emergency escape back.
+#
+# This is the test that catches everything unit tests structurally cannot: RPC
+# wiring, codec round-trips over the wire, instance transfers, and the client's
+# reconciliation loop. Run it before calling any networking change done.
+#
+#   tools/smoke.sh            # ~35s
+#   KEEP=1 tools/smoke.sh     # keep the logs and print where they are
+set -uo pipefail
+cd "$(dirname "$0")/.."
+GODOT="${GODOT:-godot}"
+PORT="${PORT:-27099}"
+SERVER_TICKS="${SERVER_TICKS:-2000}"
+CLIENT_TICKS="${CLIENT_TICKS:-1700}"
+OUT="$(mktemp -d -t transcience-smoke-XXXXXX)"
+
+cleanup() {
+  kill %1 %2 %3 2>/dev/null
+  wait 2>/dev/null
+  if [[ "${KEEP:-0}" == "1" ]]; then
+    echo "logs kept in $OUT"
+  else
+    rm -rf "$OUT"
+  fi
+}
+trap cleanup EXIT
+
+echo "smoke: server on port $PORT, logs in $OUT"
+"$GODOT" --headless --path . -- --server --port "$PORT" --autoquit "$SERVER_TICKS" \
+  > "$OUT/server.log" 2>&1 &
+
+for _ in $(seq 1 60); do
+  grep -q "SERVER_READY" "$OUT/server.log" 2>/dev/null && break
+  sleep 0.25
+done
+if ! grep -q "SERVER_READY" "$OUT/server.log" 2>/dev/null; then
+  echo "FAIL: server never became ready"; cat "$OUT/server.log"; exit 1
+fi
+
+for n in 1 2; do
+  "$GODOT" --headless --path . -- --bot --host 127.0.0.1 --port "$PORT" \
+    --name "bot$n" --autoquit "$CLIENT_TICKS" > "$OUT/bot$n.log" 2>&1 &
+  sleep 0.4
+done
+
+wait %2 %3 2>/dev/null
+wait %1 2>/dev/null
+
+fails=0
+check() { # check <label> <file> <pattern>
+  if grep -qE "$3" "$2"; then
+    echo "  ok   $1"
+  else
+    echo "  FAIL $1  (no match for /$3/ in $(basename "$2"))"
+    fails=$((fails + 1))
+  fi
+}
+refute() { # refute <label> <file> <pattern>
+  local hits
+  hits=$(grep -cE "$3" "$2" || true)
+  if [[ "$hits" == "0" ]]; then
+    echo "  ok   $1"
+  else
+    echo "  FAIL $1  ($hits line(s) matched /$3/ in $(basename "$2"))"
+    grep -E "$3" "$2" | head -5 | sed 's/^/       /'
+    fails=$((fails + 1))
+  fi
+}
+
+echo "assertions:"
+check  "server accepted bot1"        "$OUT/server.log" "joined as 'bot1'"
+check  "server accepted bot2"        "$OUT/server.log" "joined as 'bot2'"
+check  "a dungeon instance opened"   "$OUT/server.log" "opened dungeon instance"
+check  "emergency escape completed"  "$OUT/server.log" "escaped to lobby"
+check  "bot1 reached a dungeon"      "$OUT/bot1.log"   "entered instance .*DUNGEON"
+check  "bot1 returned to the lobby"  "$OUT/bot1.log"   "entered instance .*LOBBY"
+refute "no server script errors"     "$OUT/server.log" "SCRIPT ERROR|Parse Error|USER ERROR"
+refute "no client script errors"     "$OUT/bot1.log"   "SCRIPT ERROR|Parse Error|USER ERROR"
+
+echo
+if [[ $fails -eq 0 ]]; then
+  echo "SMOKE PASS"
+else
+  echo "SMOKE FAIL ($fails)"
+  echo "--- server.log (tail) ---"; tail -40 "$OUT/server.log"
+  echo "--- bot1.log (tail) ---";   tail -40 "$OUT/bot1.log"
+fi
+exit $fails