feat(admin-config-tool): drop ha/data/ entirely, match real client TLS

deploy-ha.sh no longer takes a <data-dir> argument or --build-config
flag. Every deploy now generates a fresh self-signed TLS cert/key
(openssl, RSA 2048, 10y validity) directly into the deploy dir's
certs/, and builds cluster.bin directly into controller/ctrl-1/conf/
via xceadmin -- no intermediate staging directory, nothing preserved
across runs. run-ha-soak.sh (/xce-test-ha) updated to match: dropped
its own XCE_HA_DATADIR-based precondition entirely. Updated 4 callers
(run-ha-soak.sh, test-heartbeat-tolerance.sh, test-commit-durability.sh,
both xce-deploy-ha/xce-test-ha SKILL.md docs).

Separately: xcecommon.wire.connect() was loading a client-side TLS
cert, diverging from the real reference client -- netio.c's
create_ssl_context() presents no certificate at all when acting as a
client (cert_file/key_file both NULL, bare TLS_client_method()).
Fixed connect() to match, and since nothing else consumed cert_dir
(verify_mode=CERT_NONE throughout, no CA check either), removed it
end-to-end: discovery.follow_redirects(), push.push_config()/
probe_config(), and the --cert-dir CLI flag.

Server-side cert loading (mock TLS test servers) is unaffected --
moved into a shared session-scoped tls_certs fixture (new
tests/conftest.py, openssl-generated) replacing 3 duplicated
REPO_HA_DATA_DIR/skipif blocks. Net result: those tests no longer skip
under a hermetic nix build sandbox (which never had ha/data/) --
verified 165/165 passed, 0 skipped, via both meson compile and a full
nix build --option sandbox false .#xcecore_debug rebuild (previously
128 passed / 37 skipped there).

ha/data/{xce.crt,xce.key} removed from git tracking. Requirements
2.3/2.4 and 8.3/8.4/8.5 marked superseded in requirements.md with
dated correction notes.

.kiro/specs/admin-config-tool/spec.json

@@ -1,7 +1,7 @@
 {
   "feature_name": "admin-config-tool",
   "created_at": "2026-07-06T01:30:00Z",
-  "updated_at": "2026-07-22T10:45:00Z",
+  "updated_at": "2026-07-22T14:50:00Z",
   "language": "en",
   "phase": "implementation-complete",
   "approvals": {