fix(conformance): whole-repo checks audited nested agent worktrees as source

Six discovery sites walked ROOT without pruning dot-directories, so they
descended into .claude/worktrees/agent-*/ — up to 18 full copies of the repo,
created for isolated agent runs and gitignored (.gitignore:43).

The visible half was false FAILs: four ServiceMonitors reported as selecting no
Service, and nine PrometheusRule manifests reported as "under test but not in
the repo", all of them worktree paths. The whole-repo L0 gate was red for
reasons that had nothing to do with authored surface.

The dangerous half is quieter. A check that asks "does anything in the repo
declare X" can be satisfied by a worktree copy instead of real source, so the
same bug that invents failures can also manufacture a pass. That is the reason
to fix all six sites rather than only the ones that happened to be failing.

egress-paths-selected-by-rules already had this fix and documents it (it once
saw 5 CiliumEgressGatewayPolicy objects instead of the 1 authored); this applies
the same dot-directory predicate everywhere else, which skips dot-DIRECTORIES
while still matching dot-FILES such as .sops.yaml.

platform/monitoring/tests/run.sh is the other side of the same failure: its
`--list` reported each manifest once per worktree, and the L0 check compares
that listing against the tree. Both find calls now prune .claude alongside .git.
`--list` returns 21 real pairs where it previously returned them ~19x over.

Verified in the pinned toolbox: L0 --include-scope whole-repo is 21 cases,
0 failures, 0 skips, 0 unwired (was 4 failures, then 1). L1 3/3.

The 18 stale worktrees are all on already-merged branches and remain on disk;
cleaning them up is a separate change and is no longer load-bearing for the gate.

Co-Authored-By: Claude Opus 5 <[email protected]>

conformance/tests/l0-static/alert-rules-unit-tested/check.sh

@@ -280,11 +280,16 @@ FETCH_RE = re.compile(
 #     versions.env. What is forbidden is a RULE-UNIT RUN acquiring its own engine: then the
 #     version, the network and the machine are decided silently at test time, and a missing
 #     toolchain becomes a green run instead of an exit 3.
+# NESTED WORKTREES: skip dot-DIRECTORIES (.git, .claude) while still matching dot-FILES such
+# as .sops.yaml. .claude/worktrees/agent-*/ holds full repo copies for isolated agent runs, so
+# a bare rglob from ROOT audited up to 18 duplicates of every file — which both invents FAILs
+# and, worse, can satisfy an "something declares X" check from a copy rather than real source.
+# Same fix as egress-paths-selected-by-rules. .claude/ is gitignored (.gitignore:43).
 SELF_DIR = "conformance/tests/l0-static/alert-rules-unit-tested/"
 INSTALLERS = (".gitea/workflows/scripts/install-tools.sh", "infra/devcontainer/")
 for p in sorted(ROOT.rglob("*.sh")):
     rel = str(p.relative_to(ROOT))
-    if rel.startswith((".git/", "conformance/runs/", SELF_DIR)):
+    if rel.startswith((".git/", ".claude/", "conformance/runs/", SELF_DIR)):
         continue
     try:
         text = p.read_text()
@@ -319,7 +324,7 @@ def tracked_yaml() -> list[Path]:
         return [ROOT / p for p in out.stdout.split("\0") if p]
     # No usable index (the gate container mounts a worktree whose .git points outside the
     # mount). Fall back to a filesystem walk rather than auditing nothing.
-    return sorted(p for p in ROOT.rglob("*.y*ml") if ".git/" not in str(p))
+    return sorted(p for p in ROOT.rglob("*.y*ml") if not any(part.startswith(".") for part in p.relative_to(ROOT).parent.parts))
 
 
 KIND_RE = re.compile(r"^\s*kind:\s*PrometheusRule\s*$", re.M)