perf(ci): raise pabot integration parallelism cap min(2)->min(6)

integration_tests was throttled to `min(2, _default_processes())` (commit
92e258535, a flaky-stabilization measure). Evidence from a cached CI run shows
the suite does ~47min of work serialized through 2 pabot lanes on a 32-core
runner -> ~24min wall (exactly 2x == 2 lanes), the chronic ~21-30min seen
across recent runs. It is linearly parallelism-bound.

Raise the cap to `min(6, _default_processes())`: ~4x more lanes -> projected
~6-8min wall, while staying well short of per-core fan-out (the runner reports
32 cores; behave already uses all of them). The cap is kept (not removed)
because the suite makes live LLM calls — ~149 HTTP 429 rate-limit responses
were observed even at 2-way, and unbounded fan-out would spike 429/OOM flakes
(the exact failure 92e258535 was masking). 6 is a deliberate middle ground;
TEST_PROCESSES / --processes still override.

Updates the now-stale "<=2 processes" docstrings on integration_tests and
slow_integration_tests. Behave/unit_tests parallelism (_default_processes(),
uncapped) is unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

noxfile.py

@@ -52,8 +52,12 @@ def _pabot_parallel_args(posargs: list[str]) -> list[str]:
         return []
     # Integration tests are significantly heavier than unit tests and can
     # become unstable on shared runners when pabot fans out aggressively.
-    # Keep default parallelism conservative (<=2) unless explicitly overridden.
-    pabot_default = min(2, _default_processes())
+    # Cap parallelism at 6: at the prior <=2 the ~47min suite serialized to
+    # ~24min wall on a 32-core runner (2x speedup == 2 lanes); 6 lanes cut
+    # that to ~6-8min while staying well short of the per-core fan-out that
+    # triggers LLM 429 rate-limits / OOM flakes. Override via
+    # TEST_PROCESSES / --processes.
+    pabot_default = min(6, _default_processes())
     return ["--processes", str(pabot_default)]
 
 
@@ -256,9 +260,10 @@ def build(session: nox.Session):
 def integration_tests(session: nox.Session):
     """Run Robot Framework integration tests (parallel via pabot).
 
-    Defaults to conservative parallelism (<=2 processes) to avoid
-    resource pressure in CI. Override via PABOT_PROCESSES or by passing
-    --processes/--processes=N in session arguments.
+    Defaults to parallelism capped at 6 processes (min(6, cpus)) to avoid
+    resource pressure / LLM 429 flakes in CI while still using the runner.
+    Override via TEST_PROCESSES or by passing --processes/--processes=N in
+    session arguments.
     """
     session.install("-e", ".[tests]")
     session.env["CLEVERAGENTS_AUTO_APPLY_MIGRATIONS"] = "true"
@@ -346,10 +351,10 @@ def slow_integration_tests(session: nox.Session):
     """Run Robot Framework slow integration tests (parallel via pabot).
 
     Runs all tests tagged ``slow`` that are excluded from the standard
-    ``integration_tests`` session.  Defaults to conservative parallelism
-    (<=2 processes) to avoid resource pressure in CI.  Override via
-    TEST_PROCESSES or by passing --processes/--processes=N in session
-    arguments.
+    ``integration_tests`` session.  Defaults to parallelism capped at 6
+    processes (min(6, cpus)) to avoid resource pressure / LLM 429 flakes in
+    CI.  Override via TEST_PROCESSES or by passing --processes/--processes=N
+    in session arguments.
     """
     session.install("-e", ".[tests]")
     session.env["CLEVERAGENTS_AUTO_APPLY_MIGRATIONS"] = "true"