feat(revisions): add pruning estimate and cleanup endpoints

Implemented new endpoints for estimating and pruning revisions, including detailed schemas for requests and responses. The `RevisionPruneEstimate` and `RevisionPruneResult` components were added to the OpenAPI documentation, enhancing the API's functionality for managing revision retention. Updated the backend to support these operations and integrated them into the tenant settings UI for improved user interaction.

internal/store/memory_revision_prune.go

@@ -0,0 +1,118 @@
+package store
+
+import (
+	"strings"
+	"time"
+)
+
+func (m *Memory) prunableRevisionIDsLocked(tenantID string, cutoff time.Time) []string {
+	var newest *Revision
+	for _, rev := range m.revisions {
+		if rev == nil || rev.TenantID != tenantID {
+			continue
+		}
+		if newest == nil || rev.CreatedAt.After(newest.CreatedAt) {
+			newest = rev
+		}
+	}
+	if newest == nil {
+		return nil
+	}
+	protected := map[string]struct{}{newest.ID: {}}
+	for _, sp := range m.speakers {
+		if sp == nil || sp.TenantID != tenantID {
+			continue
+		}
+		if sp.LastAppliedRevisionID != nil && strings.TrimSpace(*sp.LastAppliedRevisionID) != "" {
+			protected[strings.TrimSpace(*sp.LastAppliedRevisionID)] = struct{}{}
+		}
+	}
+	for speakerID, info := range m.publishedRevision {
+		sp, ok := m.speakers[speakerID]
+		if !ok || sp == nil || sp.TenantID != tenantID {
+			continue
+		}
+		if strings.TrimSpace(info.RevisionID) != "" {
+			protected[strings.TrimSpace(info.RevisionID)] = struct{}{}
+		}
+	}
+	var ids []string
+	for id, rev := range m.revisions {
+		if rev == nil || rev.TenantID != tenantID {
+			continue
+		}
+		if !rev.CreatedAt.Before(cutoff) {
+			continue
+		}
+		if _, keep := protected[id]; keep {
+			continue
+		}
+		ids = append(ids, id)
+	}
+	return ids
+}
+
+func revisionBytesEstimate(rev *Revision, prefixes []PrefixRow) int64 {
+	if rev == nil {
+		return 0
+	}
+	var n int64
+	n += int64(len(rev.ContentHash))
+	for _, v := range rev.PreviewFragments {
+		n += int64(len(v))
+	}
+	for _, pr := range prefixes {
+		n += int64(len(pr.Prefix) + len(pr.Source))
+	}
+	return n
+}
+
+func (m *Memory) EstimateRevisionPrune(tenantID string, cutoff time.Time, retentionMinutes int) (RevisionPruneEstimate, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	ids := m.prunableRevisionIDsLocked(tenantID, cutoff)
+	var bytes int64
+	for _, id := range ids {
+		bytes += revisionBytesEstimate(m.revisions[id], m.revPrefixes[id])
+	}
+	prefixRows := 0
+	for _, id := range ids {
+		prefixRows += len(m.revPrefixes[id])
+	}
+	return RevisionPruneEstimate{
+		RetentionMinutes:    retentionMinutes,
+		CutoffAt:            cutoff.UTC(),
+		RevisionCount:       len(ids),
+		PrefixRowCount:      prefixRows,
+		OrphanSnapshotCount: 0,
+		BytesEstimate:       bytes,
+	}, nil
+}
+
+func (m *Memory) PruneRevisionsWithStats(tenantID string, cutoff time.Time) (RevisionPruneResult, error) {
+	est, err := m.EstimateRevisionPrune(tenantID, cutoff, 0)
+	if err != nil {
+		return RevisionPruneResult{}, err
+	}
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	ids := m.prunableRevisionIDsLocked(tenantID, cutoff)
+	for _, id := range ids {
+		delete(m.revisions, id)
+		delete(m.revPrefixes, id)
+	}
+	return RevisionPruneResult{
+		DeletedRevisions:       len(ids),
+		DeletedPrefixSnapshots: 0,
+		DeletedPrefixRows:      est.PrefixRowCount,
+		BytesEstimate:          est.BytesEstimate,
+	}, nil
+}
+
+func (m *Memory) PruneRevisionsBefore(tenantID string, cutoff time.Time) (int, error) {
+	res, err := m.PruneRevisionsWithStats(tenantID, cutoff)
+	if err != nil {
+		return 0, err
+	}
+	return res.DeletedRevisions, nil
+}