refactor: rename package codexlens -> codexlens_search for independent distribution

Rename the v2 search engine package to `codexlens-search` (import as
`codexlens_search`) so it can be installed independently and consumed
by the original codex-lens as a dependency. This avoids package path
conflicts since both previously used `src/codexlens/`.

Changes:
- Rename src/codexlens/ -> src/codexlens_search/
- Update pyproject.toml: name=codexlens-search, version=0.2.0
- Update all imports across source, tests, and scripts
- Add public API exports in __init__.py (Config, SearchPipeline,
  IndexingPipeline, SearchResult, IndexStats)

37/37 tests pass. No functional changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

codex-lens-v2/tests/integration/conftest.py

@@ -3,12 +3,12 @@ import numpy as np
 import tempfile
 from pathlib import Path
 
-from codexlens.config import Config
-from codexlens.core import ANNIndex, BinaryStore
-from codexlens.embed.base import BaseEmbedder
-from codexlens.rerank.base import BaseReranker
-from codexlens.search.fts import FTSEngine
-from codexlens.search.pipeline import SearchPipeline
+from codexlens_search.config import Config
+from codexlens_search.core import ANNIndex, BinaryStore
+from codexlens_search.embed.base import BaseEmbedder
+from codexlens_search.rerank.base import BaseReranker
+from codexlens_search.search.fts import FTSEngine
+from codexlens_search.search.pipeline import SearchPipeline
 
 # Test documents: 20 code snippets with id, path, content
 TEST_DOCS = [

codex-lens-v2/tests/unit/test_config.py

@@ -1,4 +1,4 @@
-from codexlens.config import Config
+from codexlens_search.config import Config
 
 
 def test_config_instantiates_no_args():

codex-lens-v2/tests/unit/test_core.py

@@ -8,8 +8,8 @@ from pathlib import Path
 import numpy as np
 import pytest
 
-from codexlens.config import Config
-from codexlens.core import ANNIndex, BinaryStore
+from codexlens_search.config import Config
+from codexlens_search.core import ANNIndex, BinaryStore
 
 
 DIM = 32

codex-lens-v2/tests/unit/test_embed.py

@@ -18,9 +18,9 @@ def _make_fastembed_mock():
 
 _make_fastembed_mock()
 
-from codexlens.config import Config  # noqa: E402
-from codexlens.embed.base import BaseEmbedder  # noqa: E402
-from codexlens.embed.local import EMBED_PROFILES, FastEmbedEmbedder  # noqa: E402
+from codexlens_search.config import Config  # noqa: E402
+from codexlens_search.embed.base import BaseEmbedder  # noqa: E402
+from codexlens_search.embed.local import EMBED_PROFILES, FastEmbedEmbedder  # noqa: E402
 
 
 class TestEmbedSingle(unittest.TestCase):

codex-lens-v2/tests/unit/test_rerank.py

@@ -5,10 +5,10 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
-from codexlens.config import Config
-from codexlens.rerank.base import BaseReranker
-from codexlens.rerank.local import FastEmbedReranker
-from codexlens.rerank.api import APIReranker
+from codexlens_search.config import Config
+from codexlens_search.rerank.base import BaseReranker
+from codexlens_search.rerank.local import FastEmbedReranker
+from codexlens_search.rerank.api import APIReranker
 
 
 # ---------------------------------------------------------------------------

codex-lens-v2/tests/unit/test_search.py

@@ -5,16 +5,16 @@ from unittest.mock import MagicMock
 
 import pytest
 
-from codexlens.search.fts import FTSEngine
-from codexlens.search.fusion import (
+from codexlens_search.search.fts import FTSEngine
+from codexlens_search.search.fusion import (
     DEFAULT_WEIGHTS,
     QueryIntent,
     detect_query_intent,
     get_adaptive_weights,
     reciprocal_rank_fusion,
 )
-from codexlens.search.pipeline import SearchPipeline, SearchResult
-from codexlens.config import Config
+from codexlens_search.search.pipeline import SearchPipeline, SearchResult
+from codexlens_search.config import Config
 
 
 # ---------------------------------------------------------------------------