feat(harness): P2 — delete legacy customization keys & paths (rcust)

a) compose.ccci.yml is FIRST-CLASS: the harness auto-copies tests/<recipe>/
   compose.ccci.yml into the run's recipe checkout (ABRA_DIR-aware, lifecycle.
   provide_ccci_overlay) and auto-chaoses the pinned base deploy on its presence
   (kills the R7 implicit coupling). ghost/discourse install_steps.sh (copy-only
   boilerplate) deleted; CHAOS_BASE_DEPLOY removed from both metas + the registry.

b) install-time deps wiring is the ONLY mode: deps with DEPS provision BEFORE the
   single deploy; legacy post-deploy provisioning + the setup_custom_tests.sh
   invocation machinery deleted. lasuite-docs migrated to install_steps.sh OIDC
   wiring (same env names/values as the old hook — only the timing moved);
   lasuite-drive's remaining post-deploy MinIO bucket one-shot moved to ops.py
   pre_install; both setup_custom_tests.sh files deleted; OIDC_AT_INSTALL removed
   from drive/meet metas + the registry.

c) SKIP_GENERIC meta key deleted (zero users). Env form CCCI_SKIP_GENERIC* stays
   as the documented dev-only escape hatch; when active in a drone CI run the
   orchestrator prints a loud !! warning (manifest embedding lands in P5).

d) conftest cleanup: dead pre-deploy-once fixtures deployed/deployed_app deleted
   (zero users), app_domain + _short + _wait_healthy dropped (only users were the
   deleted fixtures); deps_apps+deps_creds consolidated into ONE deps fixture
   (entries expose .domain etc. as attributes; dict access intact); the 6 lasuite
   test files renamed deps_creds->deps (fixture name only — assertions and flows
   byte-identical). requires_deps marker + F2-11 skip-report plumbing unchanged.

Registry is now exactly the 14 final keys; docs §4 table regenerated. Stale
setup_custom_tests/OIDC_AT_INSTALL prose in docstrings/comments/assert MESSAGES
updated (no assert logic or expected value touched).

Verified on cc-ci: cc-ci-run -m pytest tests/unit -q -> 175 passed; scripts/lint.sh -> PASS.

tests/lasuite-drive/ops.py

@@ -5,6 +5,7 @@ in the `db` service. The backup path exercises the recipe's pg_backup.sh DB-dump
 backupbot-labelled)."""
 
 import os
+import subprocess
 import sys
 import time
 
@@ -12,6 +13,47 @@ sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "runner")
 from harness import lifecycle  # noqa: E402
 
 
+def pre_install(domain, meta):
+    """Post-deploy seed for the custom tier (the former setup_custom_tests.sh, moved here in rcust
+    P2b — install_steps.sh runs PRE-deploy and cannot touch the live stack). The deploy alone does
+    NOT create the MinIO bucket: `minio-createbuckets` is a `replicas:0` one-shot (restart_policy:
+    none) that must be triggered. The MinIO storage test asserts the bucket exists, so trigger it
+    here and poll. `--detach` is REQUIRED: the job creates the bucket then EXITS 0, so it never
+    holds a steady 1/1 replica — a blocking scale would wait forever."""
+    stack = domain.replace(".", "_")
+    print("  pre_install: creating MinIO bucket via the minio-createbuckets one-shot", flush=True)
+    subprocess.run(
+        ["docker", "service", "scale", "--detach", f"{stack}_minio-createbuckets=1"],
+        capture_output=True,
+        check=False,
+    )
+    check = (
+        'mc alias set _c http://localhost:9000 "$(cat /run/secrets/minio_ru)" '
+        '"$(cat /run/secrets/minio_rp)" >/dev/null 2>&1 && '
+        "mc ls _c/drive-media-storage >/dev/null 2>&1"
+    )
+    for i in range(30):
+        cid = subprocess.run(
+            ["docker", "ps", "-q", "-f", f"name={stack}_minio.1"],
+            capture_output=True,
+            text=True,
+            check=False,
+        ).stdout.split()
+        if cid and (
+            subprocess.run(
+                ["docker", "exec", cid[0], "sh", "-c", check], capture_output=True, check=False
+            ).returncode
+            == 0
+        ):
+            print(
+                f"  pre_install: bucket drive-media-storage present after {i + 1} poll(s)",
+                flush=True,
+            )
+            return
+        time.sleep(3)
+    raise AssertionError("minio-createbuckets one-shot did not create drive-media-storage in 90s")
+
+
 def _wait_collabora_ready(domain, timeout=420):
     """Gate the upgrade op on collabora being FULLY ready (WOPI discovery endpoint → 200), not just
     container 1/1 'running'. coolwsd takes ~2min to boot (pre-reads 1300+ l10n files + RSA keygen);