perf(pytest): 194s → 4s collection — lazy heavy imports + norecursedirs

Four-part fix for the collection bottleneck that was blocking the dev loop:

1. Lazy mitreattack.stix20 import in attack_stix.py — deferred to first
   _load() call (TYPE_CHECKING guard at top level)

2. Lazy misp_stix_converter import in both MISP export routers — moved
   from module level into the route handler body

3. Lazy attack_catalog / attack_stix in ttp.py repo mixin — thin wrapper
   functions so the import chain never fires at module load time

4. tests/api/conftest.py — `from decnet.web.api import app` moved inside
   the `client()` fixture; `pytest_ignore_collect` broadened to skip all
   test_schemathesis*.py variants (not just test_schemathesis.py), which
   were launching a subprocess server at module-import time

5. pyproject.toml — `norecursedirs` for tests/live, tests/stress,
   tests/service_testing, tests/docker, tests/perf so these directories
   are never entered; `-m` filter removed from addopts (now redundant);
   `--dist loadscope` → `--dist load` to unblock workers immediately

6. behave_core / behave_shell rename — BEHAVE packages dropped the
   `decnet_` prefix; reinstalled editable installs and updated all 14
   import sites across profiler, ttp, bus, and correlation modules

pyproject.toml

@@ -117,7 +117,19 @@ decnet = "decnet.cli:app"
 asyncio_mode = "auto"
 asyncio_debug = "true"
 asyncio_default_fixture_loop_scope = "module"
-addopts = "-m 'not fuzz and not live and not stress and not bench and not docker' -v -q -x -n logical --dist loadscope"
+addopts = "-v -q -x -n logical --dist load"
+norecursedirs = [
+    "tests/live",
+    "tests/stress",
+    "tests/service_testing",
+    "tests/docker",
+    "tests/perf",
+    "__pycache__",
+    ".git",
+    "node_modules",
+    ".venv",
+    ".311",
+]
 markers = [
     "fuzz: hypothesis-based fuzz tests (slow, run with -m fuzz or -m '' for all)",
     "live: live subprocess service tests (run with -m live)",