大改，整理项目结构，完成rust ffi调用，写好tcp接口

.github/workflows/linux.yml

@@ -1,8 +1,8 @@
 # Linux 流水线：Rust 存储 + Haskell 引擎/Web/CLI 的构建与测试。
 #
 # 这里每条命令都在 WSL Debian（cargo 1.98 / GHC 9.10.3 / stack 3.11.1）上跑通过，
-# 见仓库根 README 的「构建与测试」段。IPC 用例需要 chusql-storage 可执行文件，
-# 所以 Rust 先构建，Haskell 的 engine/web 用例才能真跑而不是 pending。
+# 见仓库根 README 的「构建与测试」段。Haskell 这边链接并装入 libchusql_core_storage.so，
+# 所以 Rust 先构建，LD_LIBRARY_PATH 指向它的输出目录，Haskell 用例才能真跑而不是 pending。
 # 打包和发版资源走 .github/workflows/release.yml（tag 触发，也可手动 dispatch）。
 name: linux
 
@@ -18,6 +18,7 @@ concurrency:
 
 env:
   CARGO_TERM_COLOR: always
+  LD_LIBRARY_PATH: ${{ github.workspace }}/chusql-core/storage/target/release
 
 jobs:
   linux:
@@ -39,24 +40,20 @@ jobs:
           path: |
             ~/.cargo/registry
             ~/.cargo/git
-            chusql-storage/target
-          key: ${{ runner.os }}-cargo-${{ hashFiles('chusql-storage/Cargo.lock') }}
+            chusql-core/storage/target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('chusql-core/storage/Cargo.lock') }}
           restore-keys: ${{ runner.os }}-cargo-
 
       - name: cargo build (release)
-        working-directory: chusql-storage
+        working-directory: chusql-core/storage
         run: cargo build --release
 
-      - name: cargo build (debug, IPC 用例要它)
-        working-directory: chusql-storage
-        run: cargo build --bin chusql-storage
-
       - name: cargo test
-        working-directory: chusql-storage
+        working-directory: chusql-core/storage
         run: cargo test --release
 
       - name: cargo clippy (-D warnings)
-        working-directory: chusql-storage
+        working-directory: chusql-core/storage
         run: cargo clippy --all-targets -- -D warnings
 
       # 故意不做 rustfmt 检查：仓库里没有 rustfmt.toml，历史代码也不是按当前 rustfmt 的
@@ -76,7 +73,8 @@ jobs:
         with:
           path: |
             ~/.stack
-            chusql-engine/.stack-work
+            chusql-core/engine/.stack-work
+            chusql-server/.stack-work
             chusql-web/.stack-work
             chusql-cli/.stack-work
           key: ${{ runner.os }}-stack-${{ hashFiles('**/stack.yaml', '**/stack.yaml.lock') }}
@@ -87,7 +85,11 @@ jobs:
         run: stack build --fast
 
       - name: engine tests
-        working-directory: chusql-engine
+        working-directory: chusql-core/engine
+        run: stack test --fast
+
+      - name: server tests
+        working-directory: chusql-server
         run: stack test --fast
 
       - name: web tests