test(snapshots): make byte/snapshot tests hermetic + re-seed baseline

The COL collision-scanner and the CLAUDE.md cascade resolve ~/.claude from
process.env.HOME (active-config-reader). Snapshot/byte CLIs were spawned with
the developer's real HOME, so they picked up installed plugins/skills and the
user CLAUDE.md — making the v5.0.0 + default-output snapshots machine- and
time-dependent. They were seeded 2026-05-01 with COL=1 (a real ~/.claude skill
collision) and drifted to COL=0 after the polyrepo split: 26 pre-existing
failures unrelated to Batch 1.

Fix (test-only, no production change):
- tests/helpers/hermetic-home.mjs — empty temp HOME, mirroring the pattern
  collision.test.mjs already uses for the COL unit test.
- 7 harnesses spawn CLIs (or call lint()) under the hermetic HOME, so output
  depends only on committed fixtures. Determinism verified across runs.
- Re-seeded all snapshots under hermetic HOME via SEED_SNAPSHOT/UPDATE_SNAPSHOT
  (added a SEED guard to the frozen v5.0.0 byte tests). Snapshots now reflect
  the fixture alone (COL=0, fixture-only activeConfig counts).
- Also re-seeded the unused env-aware snapshots (manifest/whats-active/
  plugin-health), which had baked dozens of real ~/.claude skill/plugin names
  into the committed repo — privacy cleanup.

Full suite: 812/812 green, stable across 3 runs.

tests/snapshots/v5.0.0/fix-cli.json

@@ -5,6 +5,12 @@
   "verified": [],
   "regressions": [],
   "manual": [
+    {
+      "findingId": "CA-CML-001",
+      "title": "Missing recommended sections",
+      "file": "/Users/ktg/repos/ktg-plugin-marketplace/config-audit/tests/fixtures/marketplace-medium/CLAUDE.md",
+      "recommendation": "Add sections for: Project overview, Architecture"
+    },
     {
       "findingId": "CA-GAP-001",
       "title": "No custom skills or commands",
@@ -116,14 +122,8 @@
     {
       "findingId": "CA-DIS-001",
       "title": "Tool listed in both permissions.deny and permissions.allow",
-      "file": "/Users/ktg/.claude/plugins/marketplaces/ktg-plugin-marketplace/plugins/config-audit/tests/fixtures/marketplace-medium/.claude/settings.json",
+      "file": "/Users/ktg/repos/ktg-plugin-marketplace/config-audit/tests/fixtures/marketplace-medium/.claude/settings.json",
       "recommendation": "Remove the redundant allow entries. If you actually want this tool enabled, remove it from the deny list instead. Settings should express intent clearly."
-    },
-    {
-      "findingId": "CA-COL-001",
-      "title": "Skill name \"okr-offentlig-sektor\" used by multiple plugins",
-      "file": "/Users/ktg/.claude/plugins/marketplaces/ktg-plugin-marketplace/plugins/okr/skills/okr-offentlig-sektor/SKILL.md",
-      "recommendation": "Coordinate naming across plugins, or rename one to clarify intent. The shared name forces every reader to disambiguate by source."
     }
   ],
   "backupId": null