feat: in-process HTTP search; /get /stats /audit /ingest. (#13)

bin/brain/serve.go (ladybug tags) calls internal/brain instead of exec.
HTTP tests inject a fake API so CI stays cgo-free. ExecSearcher remains
the fallback when the binary is built without system_ladybug.

internal/brain/http.go

@@ -0,0 +1,154 @@
+//go:build cgo && system_ladybug
+
+package brain
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+)
+
+// Ready opens the Ladybug file for the life of the serve process.
+func Ready() error {
+	return openBrain()
+}
+
+// HTTP is the in-process API used by bin/brain/serve.go.
+type HTTP struct{}
+
+func (HTTP) Search(_ context.Context, query string, limit int) ([]byte, error) {
+	hits, err := searchHits(query, "", "", limit)
+	if err != nil {
+		return nil, err
+	}
+	for i := range hits {
+		if hits[i].Text != "" {
+			runes := []rune(hits[i].Text)
+			if len(runes) > 280 {
+				runes = runes[:280]
+			}
+			hits[i].Snippet = string(runes)
+		}
+	}
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	enc.SetEscapeHTML(false)
+	if err := enc.Encode(toJSONOut(hits, query, "")); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+func (HTTP) Get(_ context.Context, id string, body bool) ([]byte, error) {
+	if conn == nil {
+		return nil, fmt.Errorf("brain not open")
+	}
+	stmt, err := conn.Prepare(
+		"MATCH (l:Leaf {id:$id}) RETURN l.id, l.text, l.root, l.confidence, l.source, l.type",
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer stmt.Close()
+	res, err := conn.Execute(stmt, map[string]any{"id": id})
+	if err != nil {
+		return nil, err
+	}
+	if !res.HasNext() {
+		return nil, fmt.Errorf("no leaf %s", id)
+	}
+	row, err := res.Next()
+	if err != nil {
+		return nil, err
+	}
+	vals, err := row.GetAsSlice()
+	if err != nil || len(vals) < 6 {
+		return nil, fmt.Errorf("leaf row")
+	}
+	out := map[string]any{
+		"id":         fmt.Sprint(vals[0]),
+		"root":       fmt.Sprint(vals[2]),
+		"confidence": fmt.Sprint(vals[3]),
+		"source":     fmt.Sprint(vals[4]),
+		"type":       fmt.Sprint(vals[5]),
+	}
+	if body {
+		out["text"] = fmt.Sprint(vals[1])
+	}
+	return json.Marshal(out)
+}
+
+func (HTTP) Stats(context.Context) ([]byte, error) {
+	if conn == nil {
+		return nil, fmt.Errorf("brain not open")
+	}
+	res, err := conn.Query("MATCH (l:Leaf) RETURN l.root, count(*)")
+	if err != nil {
+		return nil, err
+	}
+	byRoot := map[string]int{}
+	total := 0
+	for res.HasNext() {
+		row, err := res.Next()
+		if err != nil {
+			return nil, err
+		}
+		vals, err := row.GetAsSlice()
+		if err != nil || len(vals) < 2 {
+			continue
+		}
+		n := int(asInt(vals[1]))
+		byRoot[fmt.Sprint(vals[0])] = n
+		total += n
+	}
+	return json.Marshal(map[string]any{"total": total, "by_root": byRoot, "db": dbPath()})
+}
+
+func (HTTP) Audit(context.Context) ([]byte, error) {
+	if conn == nil {
+		return nil, fmt.Errorf("brain not open")
+	}
+	res, err := conn.Query("MATCH (l:Leaf) RETURN l.root, l.confidence, count(*)")
+	if err != nil {
+		return nil, err
+	}
+	var rows []map[string]any
+	for res.HasNext() {
+		row, err := res.Next()
+		if err != nil {
+			return nil, err
+		}
+		vals, err := row.GetAsSlice()
+		if err != nil || len(vals) < 3 {
+			continue
+		}
+		rows = append(rows, map[string]any{
+			"root":       fmt.Sprint(vals[0]),
+			"confidence": fmt.Sprint(vals[1]),
+			"count":      asInt(vals[2]),
+		})
+	}
+	return json.Marshal(map[string]any{"status": "ok", "by_confidence": rows})
+}
+
+func (HTTP) Ingest(context.Context) ([]byte, error) {
+	return json.Marshal(map[string]any{
+		"mode":    "rebuild",
+		"command": "bin/brain/index.go --rebuild",
+		"add":     "v2",
+	})
+}
+
+func asInt(v any) int64 {
+	switch n := v.(type) {
+	case int64:
+		return n
+	case int:
+		return int64(n)
+	case float64:
+		return int64(n)
+	default:
+		return 0
+	}
+}