feat(seed): fake-data generation library + fake dependency (ADR-0048 P1.1)

The pure generation half of `seed` — no command wiring yet:
- src/seed/: ColumnSpec + Generator model and a seeded StdRng; the
  type-gated name-heuristic catalogue (D7) with documented
  false-positive guards; table-context name disambiguation (D11);
  identifier (D10) and enum-ish (D12) detection; per-type + bounded-date
  generators (D8); the hand-rolled product generator (D9); and PickFrom
  for IN-CHECK / enum lists.
- Adds the `fake` crate (v5, default features). Verified: single rand
  0.10.1 (no duplication), determinism via one seeded StdRng driving
  both fake and the hand-rolled generators, security-clean across
  osv/grype/trivy.
- ADR-0048 D3 updated to record the dependency verification.

32 Tier-1 tests (exact-value via fixed --seed); 1673 lib tests pass,
clippy all-targets clean.

Cargo.toml

@@ -24,6 +24,14 @@ chrono = { version = "0.4.44", default-features = false, features = ["clock"] }
 crossterm = { version = "0.29.0", features = ["event-stream"] }
 csv = "1.4.0"
 directories = "6.0.0"
+# Realistic fake-data generators for the `seed` command (ADR-0048):
+# names, emails, addresses, companies, lorem, etc. Default features
+# only — the basic fakers need no flags; date/datetime values are
+# generated in-house (rand + the existing `chrono`) for the bounded
+# windows ADR-0048 D8 requires, so `fake`'s `chrono` feature is
+# deliberately omitted. No commerce/product module exists, so the
+# `product` generator is hand-rolled (D9).
+fake = "5"
 futures-util = "0.3.32"
 gethostname = "1.1.0"
 rand = "0.10.1"