chore: Add PyPI package support for uvx/pip installation (#1764)

* Initial plan

* Add package structure and resource path utilities

- Created langbot/ package with __init__.py and __main__.py entry point
- Added paths utility to find frontend and resource files from package installation
- Updated config loading to use resource paths
- Updated frontend serving to use resource paths
- Added MANIFEST.in for package data inclusion
- Updated pyproject.toml with build system and entry points

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Add PyPI publishing workflow and update license

- Created GitHub Actions workflow to build frontend and publish to PyPI
- Added license field to pyproject.toml to fix deprecation warning
- Updated .gitignore to exclude build artifacts
- Tested package building successfully

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Add PyPI installation documentation

- Created PYPI_INSTALLATION.md with detailed installation and usage instructions
- Updated README.md to feature uvx/pip installation as recommended method
- Updated README_EN.md with same changes for English documentation

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Address code review feedback

- Made package-data configuration more specific to langbot package only
- Improved path detection with caching to avoid repeated file I/O
- Removed sys.path searching which was incorrect for package data
- Removed interactive input() call for non-interactive environment compatibility
- Simplified error messages for version check

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Fix code review issues

- Use specific exception types instead of bare except
- Fix misleading comments about directory levels
- Remove redundant existence check before makedirs with exist_ok=True
- Use context manager for file opening to ensure proper cleanup

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* Simplify package configuration and document behavioral differences

- Removed redundant package-data configuration, relying on MANIFEST.in
- Added documentation about behavioral differences between package and source installation
- Clarified that include-package-data=true uses MANIFEST.in for data files

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

* chore: update pyproject.toml

* chore: try pack templates in langbot/

* chore: update

* chore: update

* chore: update

* chore: update

* chore: update

* chore: adjust dir structure

* chore: fix imports

* fix: read default-pipeline-config.json

* fix: read default-pipeline-config.json

* fix: tests

* ci: publish pypi

* chore: bump version 4.6.0-beta.1 for testing

* chore: add templates/**

* fix: send adapters and requesters icons

* chore: bump version 4.6.0b2 for testing

* chore: add platform field for docker-compose.yaml

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>
Co-authored-by: Junyan Qin <rockchinq@gmail.com>

src/langbot/pkg/vector/vdbs/chroma.py

@@ -0,0 +1,61 @@
+from __future__ import annotations
+import asyncio
+from typing import Any
+from chromadb import PersistentClient
+from langbot.pkg.vector.vdb import VectorDatabase
+from langbot.pkg.core import app
+import chromadb
+import chromadb.errors
+
+
+class ChromaVectorDatabase(VectorDatabase):
+    def __init__(self, ap: app.Application, base_path: str = './data/chroma'):
+        self.ap = ap
+        self.client = PersistentClient(path=base_path)
+        self._collections = {}
+
+    async def get_or_create_collection(self, collection: str) -> chromadb.Collection:
+        if collection not in self._collections:
+            self._collections[collection] = await asyncio.to_thread(
+                self.client.get_or_create_collection, name=collection
+            )
+            self.ap.logger.info(f"Chroma collection '{collection}' accessed/created.")
+        return self._collections[collection]
+
+    async def add_embeddings(
+        self,
+        collection: str,
+        ids: list[str],
+        embeddings_list: list[list[float]],
+        metadatas: list[dict[str, Any]],
+    ) -> None:
+        col = await self.get_or_create_collection(collection)
+        await asyncio.to_thread(col.add, embeddings=embeddings_list, ids=ids, metadatas=metadatas)
+        self.ap.logger.info(f"Added {len(ids)} embeddings to Chroma collection '{collection}'.")
+
+    async def search(self, collection: str, query_embedding: list[float], k: int = 5) -> dict[str, Any]:
+        col = await self.get_or_create_collection(collection)
+        results = await asyncio.to_thread(
+            col.query,
+            query_embeddings=query_embedding,
+            n_results=k,
+            include=['metadatas', 'distances', 'documents'],
+        )
+        self.ap.logger.info(f"Chroma search in '{collection}' returned {len(results.get('ids', [[]])[0])} results.")
+        return results
+
+    async def delete_by_file_id(self, collection: str, file_id: str) -> None:
+        col = await self.get_or_create_collection(collection)
+        await asyncio.to_thread(col.delete, where={'file_id': file_id})
+        self.ap.logger.info(f"Deleted embeddings from Chroma collection '{collection}' with file_id: {file_id}")
+
+    async def delete_collection(self, collection: str):
+        if collection in self._collections:
+            del self._collections[collection]
+
+        try:
+            await asyncio.to_thread(self.client.delete_collection, name=collection)
+        except chromadb.errors.NotFoundError:
+            self.ap.logger.warning(f"Chroma collection '{collection}' not found.")
+            return
+        self.ap.logger.info(f"Chroma collection '{collection}' deleted.")