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/placeholder-guard-coupling/check.sh

@@ -238,7 +238,7 @@ def bail(msg):
 
 DEF_RE = re.compile(r"^([a-z0-9_]+_is_placeholder)\(\)\s*\{")
 SELF_DIR = ROOT / "conformance" / "tests" / "l0-static" / "placeholder-guard-coupling"
-SKIP_DIRS = {".git", "_artifacts", "node_modules", ".venv"}
+SKIP_DIRS = {".git", ".claude", "_artifacts", "node_modules", ".venv"}
 
 # ------------------------------------------------------------------ discover the guard FILE
 # Hardcoding a path is what let a file that never landed disable this whole check.