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-releases.json.golden

@@ -0,0 +1,29 @@
+exit: 0
+--- stdout
+[
+  {
+    "id": 1,
+    "source_url": null,
+    "sha256": "7c1a4c209b8ce5bde9112436a0c64d66b042915995b584d2bbf7ca7b15ce81e3",
+    "as_of_date": "2026-08-31",
+    "row_count": 17,
+    "imported_at": 0
+  },
+  {
+    "id": 3,
+    "source_url": null,
+    "sha256": "7b8da1d820f67062410c48988bb6c70fec2088c24961d481d1c0fce8b9372547",
+    "as_of_date": "2026-02-27",
+    "row_count": 18,
+    "imported_at": 0
+  },
+  {
+    "id": 2,
+    "source_url": null,
+    "sha256": "efb3d8fb19c9e0d803dc1b1734c8389356605d0f78d73db6729fb76d3d75753d",
+    "as_of_date": "2026-01-30",
+    "row_count": 18,
+    "imported_at": 0
+  }
+]
+--- stderr