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-graph.json.golden

@@ -0,0 +1,58 @@
+exit: 0
+--- stdout
+{
+  "nodes": [
+    {
+      "id": "entity:14",
+      "label": "DWIMURIA INVESTAMA ANDALAN",
+      "node_type": "entity"
+    },
+    {
+      "id": "entity:15",
+      "label": "CATURGUWIRATNA SUMAPALA",
+      "node_type": "entity"
+    },
+    {
+      "id": "entity:16",
+      "label": "TRICIPTA MANDHALA GUMILANG",
+      "node_type": "entity"
+    },
+    {
+      "id": "entity:17",
+      "label": "ANTHONI SALIM",
+      "node_type": "entity"
+    },
+    {
+      "id": "ticker:BBCA",
+      "label": "BBCA",
+      "node_type": "ticker"
+    }
+  ],
+  "edges": [
+    {
+      "from": "entity:17",
+      "to": "ticker:BBCA",
+      "percentage_bps": 115,
+      "source": "ksei"
+    },
+    {
+      "from": "entity:15",
+      "to": "ticker:BBCA",
+      "percentage_bps": 102,
+      "source": "ksei"
+    },
+    {
+      "from": "entity:14",
+      "to": "ticker:BBCA",
+      "percentage_bps": 5494,
+      "source": "ksei"
+    },
+    {
+      "from": "entity:16",
+      "to": "ticker:BBCA",
+      "percentage_bps": 107,
+      "source": "ksei"
+    }
+  ]
+}
+--- stderr