ipc: one helper for the list reads on the wire (V-575)

Fourteen table entries carried the same four lines: call the CoreAPI method,
return early on error, swap a nil slice for an empty one so the wire says []
and not null. withParamsSlice holds that once and each entry is now the call
it makes.

Three id-only request types were the same struct under three names, so the
routine transitions use the idReq that was already declared and unused. The
revert reply was a map literal on one side and an anonymous struct on the
other; revertResp names it. Both are wire-identical.

internal/ipc/api.go

@@ -594,7 +594,7 @@ type setTaskFieldsReq struct {
 	BlockedOn string `json:"blocked_on,omitempty"`
 }
 
-// idReq — methods keyed by a single id.
+// idReq — methods keyed by a single id, which is every routine transition.
 type idReq struct {
 	ID int64 `json:"id"`
 }
@@ -652,6 +652,11 @@ type calendarEventsReq struct {
 type revertReq struct {
 	Key string `json:"key"`
 }
+
+// revertResp — the id of the voiding fact the revert wrote.
+type revertResp struct {
+	NewID int64 `json:"new_id"`
+}
 type writeNoteReq struct {
 	Ts        time.Time `json:"ts"`
 	Text      string    `json:"text"`
@@ -780,14 +785,6 @@ type listProposedRoutinesResp struct {
 	Routines []ProposedRoutine `json:"routines"`
 }
 
-type dismissProposedRoutineReq struct {
-	ID int64 `json:"id"`
-}
-
-type acceptProposedRoutineReq struct {
-	ID int64 `json:"id"`
-}
-
 // IntakeEvent — one entry of the unified intake journal on the wire. Mirrors
 // event.Event field for field; the ipc package does not import internal/event
 // so the wire shape stays independent of the in-process type.