docs(04): create phase plan

.planning/ROADMAP.md

@@ -149,7 +149,25 @@ Plans:
   2. A translation key `vendor.plugin::group.key` resolves for pl and en, including a CLDR plural form, loaded from per-plugin per-locale YAML files with parameter substitution.
   3. A plugin registers a mail template and layout by dotted name with the per-locale suffix convention, and it renders via `html/template` through a driver interface (SMTP via go-mail) in a test send.
 
-**Plans**: TBD
+**Plans**: 4 plans
+
+Plans:
+
+**Wave 1**
+
+- [ ] 04-01-PLAN.md — Generate compiling plugin artifacts, registry and model import checks
+
+**Wave 2** *(blocked on Wave 1 completion)*
+
+- [ ] 04-02-PLAN.md — Load namespaced translations, plurals, parameters and locale fallbacks
+
+**Wave 3** *(blocked on Wave 2 completion)*
+
+- [ ] 04-03-PLAN.md — Register, render and send plugin mail through pluggable drivers
+
+**Wave 4** *(blocked on Wave 3 completion)*
+
+- [ ] 04-04-PLAN.md — Verify scaffolding, translation and mail with unit and SMTP integration tests
 
 ### Phase 5: Data layer full fidelity