docs: expand Serenity DB migration kanban wave

docs/planning/SERENITY_CLEANUP_WAVE_1.md

@@ -316,17 +316,56 @@ Definition of done:
 - no public path depends on it
 - container removed
 
-### Card D1 — prepare GameVault migration to PD
+### Card D1 — choose PD target layout for GameVault and RomM wave
 Definition of done:
-- target DB/appdata path chosen
-- export/import path documented
-- cutover checklist ready
+- PD target appdata paths chosen for both apps
+- decision recorded to use PD shared-postgres for GameVault unless blocked
+- decision recorded to use PD shared-mariadb for RomM unless blocked
+- required PD mount paths for libraries/assets/resources identified
 
-### Card D2 — prepare RomM migration to PD
+### Card D2 — stage PD database targets for the wave
 Definition of done:
-- target DB/appdata path chosen
-- export/import path documented
-- cutover checklist ready
+- GameVault target DB/user created on PD shared-postgres or explicit exception documented
+- RomM target DB/user created on PD shared-mariadb or explicit exception documented
+- connection details verified from the future PD app network context
+- migration rollback notes captured before any source export
+
+### Card D3 — export and validate Serenity source databases
+Definition of done:
+- `gamevault` Postgres dump exported from Serenity and integrity-checked
+- `romm` MariaDB dump exported from Serenity and integrity-checked
+- source app versions and DB container versions recorded alongside dumps
+- Postgres collation-version warning captured as a post-import remediation item
+
+### Card D4 — sync appdata for GameVault and RomM to PD staging paths
+Definition of done:
+- GameVault config/media/log paths copied to PD staging
+- RomM config/assets/resources paths copied to PD staging
+- large library mounts intentionally re-used from canonical storage instead of blindly duplicating data
+- ownership/permissions on PD staging paths verified
+
+### Card D5 — cut over GameVault to PD
+Definition of done:
+- Serenity GameVault stopped only for the final cutover window
+- PD GameVault starts against the PD target Postgres DB
+- login, library visibility, metadata behavior, and save/upload paths verified
+- public/LAN route updated if needed and verified
+- Serenity `postgresql15` kept in place but clearly marked retirement-ready if cutover succeeds
+
+### Card D6 — cut over RomM to PD
+Definition of done:
+- Serenity RomM stopped only for the final cutover window
+- PD RomM starts against the PD target MariaDB DB
+- UI, library visibility, assets/resources, background jobs, and metadata behavior verified
+- public/LAN route updated if needed and verified
+- Serenity `MariaDB-Official` kept in place but clearly marked retirement-ready if cutover succeeds
+
+### Card D7 — retire Serenity DB remnants after cooldown
+Definition of done:
+- GameVault and RomM remain healthy on PD through an observation window
+- Serenity `postgresql15` and `MariaDB-Official` are stopped and removed only after successful PD validation
+- Serenity-side DB appdata is retained for cooldown/rollback, not deleted immediately
+- docs and host inventory updated to show Serenity no longer carries those DB pairs
 
 ## Open item that still needs verification