kbsearch: Go implementation with daemon model serving

- New nested module bin/kbsearch with Go implementation of bin/kb/search
- Embedding model (potion-multilingual-128M) served by localhost daemon
  so repeated CLI calls reuse the loaded model
- Bash launcher bin/kb/search builds binary on first run, caches to var/bin/
- Hybrid FTS + vector search (RRF k=60) matching Python kblib behavior
- YAML output via port of yamlout.py (ordered keys, same format)
- JSON output with proper field order
- All flags: --root, --repo, -n, --json, --list-model
- Root go.mod reverted to 1.25.0 (kbsearch is isolated nested module)
- CI passes: go test ./... and go vet ./... unaffected by kbsearch

bin/kb/search

@@ -1,76 +1,34 @@
-#!/usr/bin/env python3
-"""kb/search - deduction search over the 2dph brain.
+#!/usr/bin/env bash
+# bin/kb/search - Go deduction search over the brain (model served by daemon).
+# Builds the kbsearch binary on first run / when source changes, then execs it.
+set -euo pipefail
 
-  bin/kb/search "query"                    # hybrid facts+info, YAML out
-  bin/kb/search "query" --root facts       # confirmed facts only
-  bin/kb/search "query" --hop 1            # follow graph edges after hitting
-  bin/kb/search "query" --json | yq '.'
-  bin/kb/search "query" -n 5               # more results
+KB="$(cd "$(dirname "$0")/../.." && pwd)"
+BIN="$KB/var/bin/kbsearch"
+SRC="$KB/bin/kbsearch"
 
-Deduction order: facts root first (confirmed answers with evidence links),
-then info root (marked `(not confirmed)`). --root restricts to one root.
---hop N walks FROM_FILE edges (sibling leafs in the same source file).
-"""
-from __future__ import annotations
+mkdir -p "$KB/var/bin"
 
-import json
-import sys
-from pathlib import Path
+# Rebuild if binary missing or any .go source newer
+need_build=0
+if [ ! -x "$BIN" ]; then
+    need_build=1
+else
+    # Check if any .go in kbsearch is newer than binary
+    while IFS= read -r -d '' f; do
+        if [ "$f" -nt "$BIN" ]; then
+            need_build=1
+            break
+        fi
+    done < <(find "$SRC" -name '*.go' -print0 2>/dev/null)
+fi
 
-ROOT = Path(__file__).resolve().parents[2]
-sys.path.insert(0, str(ROOT / "bin" / "tools"))
+if [ "$need_build" -eq 1 ]; then
+    echo "Building kbsearch..." >&2
+    (cd "$SRC" && \
+        CGO_CFLAGS="-I$KB/lib-ladybug" \
+        CGO_LDFLAGS="-L$KB/lib-ladybug -Wl,-rpath,$KB/lib-ladybug" \
+        go build -tags system_ladybug -o "$BIN" .) || exit 1
+fi
 
-from kblib import connect, hybrid_search, init_schema, open_readonly, query_fts  # noqa: E402
-from yamlout import to_yaml  # noqa: E402
-import ladybug  # noqa: E402
-
-
-def main(argv: list[str]) -> int:
-    import argparse
-    p = argparse.ArgumentParser(description="deduction search over the brain")
-    p.add_argument("query")
-    p.add_argument("--root", choices=("facts", "info", None), default=None)
-    p.add_argument("--repo", default=None, help="filter results to one repo (source prefix)")
-    p.add_argument("--hop", type=int, default=0)
-    p.add_argument("-n", "--limit", type=int, default=10)
-    p.add_argument("--json", action="store_true")
-    a = p.parse_args(argv)
-
-    try:
-        db, conn = open_readonly()
-    except FileNotFoundError as e:
-        print(e, file=sys.stderr)
-        return 1
-
-    from model2vec import StaticModel
-    model = StaticModel.from_pretrained("minishlab/potion-multilingual-128M")
-    emb = model.encode([a.query])[0].astype(float).tolist()
-
-    rhs: list[dict] = []
-    try:
-        rhs = query_fts(conn, a.query, a.limit * 2)
-    except Exception:
-        rhs = []
-
-    results = hybrid_search(conn, emb, rhs, a.limit)
-    if a.root:
-        results = [h for h in results if h["root"] == a.root]
-    if a.repo:
-        repo = a.repo
-        results = [h for h in results if repo in (h.get("source") or "")]
-
-    for hit in results:
-        hit.pop("rrf", None)
-        if hit.get("text"):
-            hit["snippet"] = hit["text"][:280]
-
-    out = {"query": a.query, "root_filter": a.root or "facts+info",
-           "count": len(results), "results": results}
-    print(json.dumps(out, indent=2, ensure_ascii=False) if a.json else to_yaml(out))
-    conn.close()
-    db.close()
-    return 0
-
-
-if __name__ == "__main__":
-    sys.exit(main(sys.argv[1:]))
+exec "$BIN" "$@"