feat(ingestion): add wiki package with Page types and slug generation

ingestion/internal/wiki/slug.go

@@ -0,0 +1,28 @@
+// ingestion/internal/wiki/slug.go
+package wiki
+
+import (
+	"strings"
+	"unicode"
+)
+
+// Slug converts a title to a kebab-case slug suitable for wiki filenames.
+// Rules: lowercase, spaces/hyphens/underscores → hyphens, strip everything else.
+func Slug(title string) string {
+	var b strings.Builder
+	prevHyphen := true // start true to trim leading hyphens
+	for _, r := range strings.ToLower(title) {
+		switch {
+		case r == ' ' || r == '-' || r == '_':
+			if !prevHyphen {
+				b.WriteRune('-')
+				prevHyphen = true
+			}
+		case unicode.IsLetter(r) || unicode.IsDigit(r):
+			b.WriteRune(r)
+			prevHyphen = false
+		// all other characters (apostrophes, colons, dots, etc.) are dropped
+		}
+	}
+	return strings.TrimRight(b.String(), "-")
+}