Replace stdlib sort with github.com/carli2/hybridsort (#83)

Large-data hot paths (index.go, shard.go) use HybridSort with
value-based less for natural run detection + buffered merge.
All other sort.Slice/sort.Sort calls use hybridsort.Slice/SliceStable.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: carli2

go.sum

@@ -38,14 +38,6 @@ github.com/aws/aws-sdk-go-v2/service/sts v1.41.6 h1:5fFjR/ToSOzB2OQ/XqWpZBmNvmP/
 github.com/aws/aws-sdk-go-v2/service/sts v1.41.6/go.mod h1:qgFDZQSD/Kys7nJnVqYlWKnh0SSdMjAi0uSwON4wgYQ=
 github.com/aws/smithy-go v1.24.0 h1:LpilSUItNPFr1eY85RYgTIg5eIEPtvFbskaFcmmIUnk=
 github.com/aws/smithy-go v1.24.0/go.mod h1:LEj2LM3rBRQJxPZTB4KuzZkaZYnZPnvgIhb4pu07mx0=
-github.com/carli2/hybridsort v0.0.0-20260319191746-8429712d7a1c h1:h9PAuqFyYi8dCWABYlaiJjzpY9KmzXZsNUPU6RnZrGI=
-github.com/carli2/hybridsort v0.0.0-20260319191746-8429712d7a1c/go.mod h1:ZSL9x9C2qLz4fL7VZdCs7QZCqNBkBZkcYtY0Fcw2Ezo=
-github.com/carli2/hybridsort v0.0.0-20260319194603-ddd18ae27ffa h1:nS1j57V0eKCC2ydo3ja9QTP2hl0EI/vntgp8cVJ1rVw=
-github.com/carli2/hybridsort v0.0.0-20260319194603-ddd18ae27ffa/go.mod h1:ZSL9x9C2qLz4fL7VZdCs7QZCqNBkBZkcYtY0Fcw2Ezo=
-github.com/carli2/hybridsort v0.0.0-20260319211747-bc628a3877c1 h1:YhHOYcRJ5z+Vc2ly2qJnAAF15qPYxQR39sibTmDfKUM=
-github.com/carli2/hybridsort v0.0.0-20260319211747-bc628a3877c1/go.mod h1:ZSL9x9C2qLz4fL7VZdCs7QZCqNBkBZkcYtY0Fcw2Ezo=
-github.com/carli2/hybridsort v0.0.0-20260319212745-ac6f7edeb1b1 h1:L5JNXOg6HLjGecOzzrxR9itw3Dal1NSd4nfXlPG4/tw=
-github.com/carli2/hybridsort v0.0.0-20260319212745-ac6f7edeb1b1/go.mod h1:ZSL9x9C2qLz4fL7VZdCs7QZCqNBkBZkcYtY0Fcw2Ezo=
 github.com/carli2/hybridsort v0.0.0-20260319220658-610599b2851c h1:KLKFOH2gyHQ03+t9t29pQufv+GGVRBYCOTw3VEqFOX8=
 github.com/carli2/hybridsort v0.0.0-20260319220658-610599b2851c/go.mod h1:ZSL9x9C2qLz4fL7VZdCs7QZCqNBkBZkcYtY0Fcw2Ezo=
 github.com/carli2/text v0.34.1-0.20260305004517-20c7a406302a h1:qnerlW5tSOXN0OYjUAscEZWzTzTzSP+ASRJwpUdfya4=

storage/index.go

@@ -19,11 +19,11 @@ package storage
 
 import "sort"
 import "sync"
-import "github.com/carli2/hybridsort"
 import "sync/atomic"
 import "time"
 import "strings"
 
+import "github.com/carli2/hybridsort"
 import "github.com/google/btree"
 import "github.com/launix-de/memcp/scm"
 
@@ -507,16 +507,16 @@ func (s *StorageIndex) buildIndex(cols []colGetter) {
 		}
 		// sort indexes; skip non-sorted matcher columns (they don't affect
 		// sort order, they are query-level overlays for pruning)
-		hybridsort.Slice(tmp, func(i, j int) bool {
+		hybridsort.HybridSort(tmp, func(a, b uint32) bool {
 			for colIdx, g := range cols {
 				if len(s.ColMatchers) > colIdx && !s.ColMatchers[colIdx].IsSorted() {
 					continue
 				}
-				a := g.get(tmp[i])
-				b := g.get(tmp[j])
-				if scm.Less(a, b) {
+				va := g.get(a)
+				vb := g.get(b)
+				if scm.Less(va, vb) {
 					return true // less
-				} else if !scm.Equal(a, b) {
+				} else if !scm.Equal(va, vb) {
 					return false // greater
 				}
 				// otherwise: next iteration

storage/shard.go

@@ -17,7 +17,6 @@ Copyright (C) 2023-2026  Carl-Philip Hänsch
 package storage
 
 import "fmt"
-import "github.com/carli2/hybridsort"
 import "sync"
 import "sync/atomic"
 import "time"
@@ -26,6 +25,7 @@ import "reflect"
 import "runtime"
 import "encoding/json"
 import "encoding/binary"
+import "github.com/carli2/hybridsort"
 import "github.com/google/uuid"
 import "github.com/jtolds/gls"
 import "github.com/launix-de/memcp/scm"
@@ -2078,10 +2078,9 @@ func (t *storageShard) rebuild(all bool) *storageShard {
 				}
 			}
 			idxCols := idx.Cols
-			hybridsort.Slice(sortPerm, func(a, b int) bool {
+			hybridsort.HybridSort(sortPerm, func(idA, idB uint32) bool {
 				for _, colName := range idxCols {
 					var va, vb scm.Scmer
-					idA, idB := sortPerm[a], sortPerm[b]
 					if idA < t.main_count {
 						va = t.columns[colName].GetValue(idA)
 					} else {