Unify previous source resolution

docs/internal/command-restore.md

@@ -43,8 +43,9 @@ Planner behavior:
 For a non-dry-run restore, planning/classification happens only after acquiring
 the session lock. Runner manifest/reuse checks acquire that same lock first.
 
-Previous-cache files are planned separately through `previouscache.BuildPlan`
-when configured previous-session requirements exist.
+Previous-cache readiness is resolved through `previouscache.Resolve` for restore,
+prepare, status, and validation. A committed source is selected only by its
+exact source identity; legacy fallback remains isolated and rejects ambiguity.
 
 ## Execution Contract
 
@@ -56,6 +57,9 @@ Execution order and safety:
 - manifest replacement is validated before rename;
 - each committed object is verified against its declared checksum, size, and
   generation before installation;
+- a committed manifest already verified during discovery is retained for the
+  matching restore action and revalidated before installation, avoiding a
+  second body transfer;
 - failed installs do not roll back files already written in the same execution.
 - a durable `.restore-incomplete.json` marker is written before installation.
   It blocks runners until a restore retry completes all verified installs and
@@ -75,7 +79,8 @@ Audio restore path:
 
 ## Reporting Contract
 
-- dry-run mode prints a summary and performs no local writes;
+- dry-run mode prints a summary, performs no durable session writes, and may
+  read remote current-state or object-identity data to produce that summary;
 - execution mode persists the canonical restore report described in
   [Operations](../operations.md#restore-workflow);
 - report includes plan counts, per-action status, and execution failures.