test: add golden output parity gate and live A/B compare

Phase 0 of docs/DESIGN.md, before any refactor code:

- tests/golden.rs runs every case in tests/golden/cases.toml (126
  outputs across help, completions, config, cache, all stocks commands
  on MSN and Yahoo mocks, error paths, and ownership queries on a seeded
  fixture DB) and compares exit code, stdout, and stderr byte for byte.
  Regenerate only with UPDATE_GOLDEN=1 for a reviewed output change.
- scripts/live-smoke.sh --compare <old-idx> runs each live case with
  both binaries and fails on differing exit codes, added/missing/retyped
  JSON keys, or changed values for slow-moving data.
- Exclude golden files from the whitespace/EOF pre-commit fixers, which
  would otherwise rewrite pinned help output.

Both gates were fault-injected: a one-word table change fails exactly
the three history goldens, and a binary dropping profile.long_name fails
only the profile live comparison.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/golden/ownership-ticker-ksei.json.golden

@@ -0,0 +1,67 @@
+exit: 0
+--- stdout
+{
+  "ticker": {
+    "id": 4,
+    "code": "BBCA",
+    "name": "BANK CENTRAL ASIA Tbk",
+    "sector": null
+  },
+  "ksei_as_of": "2026-08-31",
+  "bing_as_of": null,
+  "holders": [
+    {
+      "rank": 1,
+      "source": "ksei",
+      "name": "DWIMURIA INVESTAMA ANDALAN",
+      "entity_id": 14,
+      "investor_type": "CORPORATE",
+      "locality": "Local",
+      "shares": 67729950000,
+      "percentage_bps": 5494,
+      "signal": null
+    },
+    {
+      "rank": 2,
+      "source": "ksei",
+      "name": "ANTHONI SALIM",
+      "entity_id": 17,
+      "investor_type": "INDIVIDUAL",
+      "locality": "Local",
+      "shares": 1416306835,
+      "percentage_bps": 115,
+      "signal": null
+    },
+    {
+      "rank": 3,
+      "source": "ksei",
+      "name": "TRICIPTA MANDHALA GUMILANG",
+      "entity_id": 16,
+      "investor_type": "CORPORATE",
+      "locality": "Local",
+      "shares": 1313250000,
+      "percentage_bps": 107,
+      "signal": null
+    },
+    {
+      "rank": 4,
+      "source": "ksei",
+      "name": "CATURGUWIRATNA SUMAPALA",
+      "entity_id": 15,
+      "investor_type": "CORPORATE",
+      "locality": "Local",
+      "shares": 1261750000,
+      "percentage_bps": 102,
+      "signal": null
+    }
+  ],
+  "concentration": {
+    "top1_bps": 5494,
+    "top3_bps": 5716,
+    "hhi": 3021,
+    "free_float_bps": 4182,
+    "holder_count": 4
+  },
+  "flow": null
+}
+--- stderr