chore: 添加虚拟环境到仓库

- 添加 backend_service/venv 虚拟环境
- 包含所有Python依赖包
- 注意：虚拟环境约393MB，包含12655个文件

backend_service/venv/lib/python3.13/site-packages/chromadb/migrations/metadb/00001-embedding-metadata.sqlite.sql

@@ -0,0 +1,24 @@
+CREATE TABLE embeddings (
+    id INTEGER PRIMARY KEY,
+    segment_id TEXT NOT NULL,
+    embedding_id TEXT NOT NULL,
+    seq_id BLOB NOT NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    UNIQUE (segment_id, embedding_id)
+);
+
+CREATE TABLE embedding_metadata (
+    id INTEGER REFERENCES embeddings(id),
+    key TEXT NOT NULL,
+    string_value TEXT,
+    int_value INTEGER,
+    float_value REAL,
+    PRIMARY KEY (id, key)
+);
+
+CREATE TABLE max_seq_id (
+    segment_id TEXT PRIMARY KEY,
+    seq_id BLOB NOT NULL
+);
+
+CREATE VIRTUAL TABLE embedding_fulltext USING fts5(id, string_value);

backend_service/venv/lib/python3.13/site-packages/chromadb/migrations/metadb/00002-embedding-metadata.sqlite.sql

@@ -0,0 +1,5 @@
+-- SQLite does not support adding check with alter table, as a result, adding a check
+-- involve creating a new table and copying the data over. It is over kill with adding
+-- a boolean type column. The application write to the table needs to ensure the data
+-- integrity.
+ALTER TABLE embedding_metadata ADD COLUMN bool_value INTEGER

backend_service/venv/lib/python3.13/site-packages/chromadb/migrations/metadb/00003-full-text-tokenize.sqlite.sql

@@ -0,0 +1,3 @@
+CREATE VIRTUAL TABLE embedding_fulltext_search USING fts5(string_value, tokenize='trigram');
+INSERT INTO embedding_fulltext_search (rowid, string_value) SELECT rowid, string_value FROM embedding_metadata;
+DROP TABLE embedding_fulltext;

backend_service/venv/lib/python3.13/site-packages/chromadb/migrations/metadb/00004-metadata-indices.sqlite.sql

@@ -0,0 +1,3 @@
+CREATE INDEX IF NOT EXISTS embedding_metadata_int_value ON embedding_metadata (key, int_value) WHERE int_value IS NOT NULL;
+CREATE INDEX IF NOT EXISTS embedding_metadata_float_value ON embedding_metadata (key, float_value) WHERE float_value IS NOT NULL;
+CREATE INDEX IF NOT EXISTS embedding_metadata_string_value ON embedding_metadata (key, string_value) WHERE string_value IS NOT NULL;

backend_service/venv/lib/python3.13/site-packages/chromadb/migrations/metadb/00005-max-seq-id-int.sqlite.sql

@@ -0,0 +1,27 @@
+ALTER TABLE max_seq_id ADD COLUMN int_seq_id INTEGER;
+
+-- Convert 8 byte wide big-endian integer as blob to native 64 bit integer.
+-- Adapted from https://stackoverflow.com/a/70296198.
+UPDATE max_seq_id SET int_seq_id = (
+  SELECT (
+       (instr('123456789ABCDEF', substr(hex(seq_id), -1 , 1)) <<  0)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -2 , 1)) <<  4)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -3 , 1)) <<  8)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -4 , 1)) << 12)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -5 , 1)) << 16)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -6 , 1)) << 20)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -7 , 1)) << 24)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -8 , 1)) << 28)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -9 , 1)) << 32)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -10, 1)) << 36)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -11, 1)) << 40)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -12, 1)) << 44)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -13, 1)) << 48)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -14, 1)) << 52)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -15, 1)) << 56)
+     | (instr('123456789ABCDEF', substr(hex(seq_id), -16, 1)) << 60)
+    )
+);
+
+ALTER TABLE max_seq_id DROP COLUMN seq_id;
+ALTER TABLE max_seq_id RENAME COLUMN int_seq_id TO seq_id;