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

decnet/web/db/sqlmodel_repo/ttp.py

@@ -20,8 +20,6 @@ from typing import Any
 from sqlalchemy import func, select
 from sqlmodel import col
 
-from decnet.ttp.attack_catalog import technique_name as _technique_name
-from decnet.ttp.attack_stix import mitre_url_for as _mitre_url_for
 from decnet.web.db.models import (
     Attacker,
     AttackerIdentity,
@@ -34,6 +32,16 @@ from decnet.web.db.models.canary import CanaryTrigger
 from decnet.web.db.sqlmodel_repo._helpers import _MixinBase
 
 
+def _technique_name(tid: str | None) -> str | None:
+    from decnet.ttp.attack_catalog import technique_name  # heavy — lazy on first call
+    return technique_name(tid)
+
+
+def _mitre_url_for(tid: str | None) -> str | None:
+    from decnet.ttp.attack_stix import mitre_url_for  # heavy — lazy on first call
+    return mitre_url_for(tid)
+
+
 # Confidence floor: tags computed below this value are silently dropped
 # at insert time. Pinned by tests/ttp/test_confidence.py.
 _CONFIDENCE_FLOOR: float = 0.3