fix(postgres/psql): normalize REL_17_0 tag format to 17.0

Strip REL_ prefix and convert underscores to dots in a per-package
normalizer rather than config, matching the convention for watchexec.

internal/classifypkg/classifypkg.go

@@ -32,6 +32,7 @@ import (
 	"github.com/webinstall/webi-installers/internal/releases/node"
 	"github.com/webinstall/webi-installers/internal/releases/ollama"
 	"github.com/webinstall/webi-installers/internal/releases/pwsh"
+	"github.com/webinstall/webi-installers/internal/releases/postgres"
 	"github.com/webinstall/webi-installers/internal/releases/watchexec"
 	"github.com/webinstall/webi-installers/internal/releases/xcaddy"
 	"github.com/webinstall/webi-installers/internal/releases/zigdist"
@@ -127,6 +128,8 @@ func NormalizeVersions(pkg string, assets []storage.Asset) {
 				assets[i].Version = "0." + v[1:] + ".0"
 			}
 		}
+	case "postgres", "psql":
+		postgres.NormalizeVersions(assets)
 	case "watchexec":
 		watchexec.NormalizeVersions(assets)
 	}

internal/releases/postgres/versions.go

@@ -0,0 +1,16 @@
+package postgres
+
+import (
+	"strings"
+
+	"github.com/webinstall/webi-installers/internal/storage"
+)
+
+// NormalizeVersions strips the REL_ prefix and converts underscores to dots.
+// GitHub tags are "REL_17_0" → version becomes "17.0".
+func NormalizeVersions(assets []storage.Asset) {
+	for i := range assets {
+		v := strings.TrimPrefix(assets[i].Version, "REL_")
+		assets[i].Version = strings.ReplaceAll(v, "_", ".")
+	}
+}