feat(lifecycle): plain-language generation diffs (#82)

nomarchy-what-changed wraps nvd into "N added, M removed, K updated"
summaries. nomarchy-rebuild / nomarchy-home print full nvd and toast
the one-liner; System › What changed? offers toast + floating report.
checks.what-changed fixtures nvd via NOMARCHY_NVD.

Verified: V2 — flake check --no-build; checks.what-changed green;
local smoke on real HM generations.

agent/JOURNAL.md

@@ -19,6 +19,17 @@ Template:
 
 ---
 
+## 2026-07-11 — #82 generation readability
+- **Task:** NEXT #82 — plain-language “what changed last rebuild”.
+- **Did:** `pkgs/nomarchy-what-changed` (nvd → “N added, M removed, K
+  updated”); wired into lifecycle post-`nomarchy-rebuild` / `nomarchy-home`
+  (full nvd + notify toast); System › What changed? (toast + floating
+  full report). `checks.what-changed` with NOMARCHY_NVD fixture. Closed #82.
+- **Verified:** **V2** — checks.what-changed green; local smoke on real
+  HM gens (“Desktop: 1 added, 1 removed”) + fixture counts.
+- **Pending:** —
+- **Next suggestion:** #83 doctor pre-activate fail flag or #85 docs.
+
 ## 2026-07-11 — #81 first-boot welcome toast
 - **Task:** NEXT #81 — dismissible “you're set” card (`VISION § B`).
 - **Did:** `pkgs/nomarchy-first-boot` + user oneshot