feat(seed): SeedResult outcome, capped preview, advisory, count cap (ADR-0048 P1.3c)

A dedicated SeedResult replaces the borrowed insert outcome (X5):
- CommandOutcome::Seed + DslSeedSucceeded event + handle_dsl_seed_success
  render: the echo, "N row(s) seeded into T", a capped preview table
  (D18, first 20 rows; full count always reported), and a Hint-styled
  advisory naming enum-ish / un-derivable-CHECK columns filled with
  generic text (D12/D13, Phase-1 wording).
- SeedResult carries requested vs produced, so a junction cap is now
  reported to the user, not only logged.
- Count cap (D6): a seed over 10000 rows is refused with a friendly error.
- Catalog keys ok.rows_seeded / seed.capped / seed.advisory_generic.

4 new tests (advisory flag, IN-check not flagged, preview cap, excess
count). 2346 pass / 0 fail / 0 skip, clippy clean.

src/friendly/keys.rs

@@ -550,7 +550,10 @@ pub const KEYS_AND_PLACEHOLDERS: &[(&str, &[&str])] = &[
     ("ok.index_dropped_with_column", &["index"]),
     ("ok.rows_deleted", &["count"]),
     ("ok.rows_inserted", &["count"]),
+    ("ok.rows_seeded", &["count", "table"]),
     ("ok.rows_updated", &["count"]),
+    ("seed.capped", &["requested"]),
+    ("seed.advisory_generic", &["columns"]),
     // ---- Client-side success notes (ADR-0017 §6, ADR-0018 §9) ----
     ("client_side.auto_fill_add_serial", &["count"]),
     ("client_side.auto_fill_add_shortid", &["count"]),

src/friendly/strings/en-US.yaml

@@ -983,6 +983,13 @@ db:
 # template couldn't provide. Re-introduce a key here if a non-English
 # locale lands.)
 
+# Seed-command notes (ADR-0048): the cap note when the unique-value
+# space is exhausted, and the advisory that flags columns filled with
+# generic text that look like fixed value sets.
+seed:
+  capped: "(of {requested} requested — ran out of distinct value combinations)"
+  advisory_generic: "{columns} filled with generic text — they look like fixed value sets."
+
 ok:
   # ADR-0040: the generic `[ok] <verb> <subject>` summary line was
   # retired — a successful command's echo line now carries a ✓
@@ -990,6 +997,7 @@ ok:
   # per-operation row-count footers below still convey real payload
   # and are unchanged.
   rows_inserted: "  {count} row(s) inserted"
+  rows_seeded: "  {count} row(s) seeded into {table}"
   rows_updated: "  {count} row(s) updated"
   rows_deleted: "  {count} row(s) deleted"
   # Shown beneath a `drop column --cascade` summary, once per