build: make Rust toolchain optional, only required for PROXYSQLGENAI

- Rust/cargo checks now only run when PROXYSQLGENAI=1
- sqlite3 target now only depends on GenAI extensions (vec.o, libsqlite_rembed.a)
  when PROXYSQLGENAI is enabled
- Removed duplicate target definitions for sqlite-vec and sqlite-rembed

deps/Makefile

@@ -4,14 +4,16 @@ PROXYSQL_PATH := $(shell while [ ! -f ./src/proxysql_global.cpp ]; do cd ..; don
 
 include $(PROXYSQL_PATH)/include/makefiles_vars.mk
 
-# Rust toolchain detection
+# Rust toolchain detection (only needed for PROXYSQLGENAI)
+ifeq ($(PROXYSQLGENAI),1)
 RUSTC := $(shell which rustc 2>/dev/null)
 CARGO := $(shell which cargo 2>/dev/null)
 ifndef RUSTC
-$(error "rustc not found. Please install Rust toolchain")
+$(error "rustc not found. Please install Rust toolchain (required for PROXYSQLGENAI)")
 endif
 ifndef CARGO
-$(error "cargo not found. Please install Rust toolchain")
+$(error "cargo not found. Please install Rust toolchain (required for PROXYSQLGENAI)")
+endif
 endif
 
 # SQLite environment variables for sqlite-rembed build
@@ -285,7 +287,17 @@ sqlite3/libsqlite_rembed.a: sqlite3/sqlite-rembed-0.0.1-alpha.9.tar.gz
 	cd sqlite3/sqlite-rembed-source && SQLITE3_INCLUDE_DIR=$(SQLITE3_INCLUDE_DIR) SQLITE3_LIB_DIR=$(SQLITE3_LIB_DIR) SQLITE3_STATIC=1 $(CARGO) build --release --features=sqlite-loadable/static --lib
 	cp sqlite3/sqlite-rembed-source/target/release/libsqlite_rembed.a sqlite3/libsqlite_rembed.a
 
+ifeq ($(PROXYSQLGENAI),1)
 sqlite3: sqlite3/sqlite3/sqlite3.o sqlite3/sqlite3/vec.o sqlite3/libsqlite_rembed.a
+else
+sqlite3: sqlite3/sqlite3/sqlite3.o
+endif
+
+# sqlite-vec: Vector similarity search extension (for GenAI)
+sqlite-vec: sqlite3/sqlite3/vec.o
+
+# sqlite-rembed: Remote embedding extension (Rust-based, for GenAI)
+sqlite-rembed: sqlite3/libsqlite_rembed.a
 
 
 libconfig/libconfig/out/libconfig++.a:
@@ -375,24 +387,6 @@ libscram/lib/libscram.a:postgresql/postgresql/src/interfaces/libpq/libpq.a
 libscram: libscram/lib/libscram.a
 
 
-# sqlite-vec: Vector similarity search extension (for GenAI)
-sqlite3/sqlite3/vec.o: sqlite3/sqlite3/sqlite3.o
-	cd sqlite3/sqlite3 && cp ../sqlite-vec-source/sqlite-vec.c . && cp ../sqlite-vec-source/sqlite-vec.h .
-	cd sqlite3/sqlite3 && ${CC} ${MYCFLAGS} -fPIC -c -o vec.o sqlite-vec.c -DSQLITE_CORE -DSQLITE_VEC_STATIC -DSQLITE_ENABLE_MEMORY_MANAGEMENT -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_FTS5 -DSQLITE_DLL=1
-
-sqlite-vec: sqlite3/sqlite3/vec.o
-
-# sqlite-rembed: Remote embedding extension (Rust-based, for GenAI)
-sqlite3/libsqlite_rembed.a: sqlite3/sqlite-rembed-0.0.1-alpha.9.tar.gz
-	cd sqlite3 && rm -rf sqlite-rembed-*/ sqlite-rembed-source/ || true
-	cd sqlite3 && tar -zxf sqlite-rembed-0.0.1-alpha.9.tar.gz
-	mv sqlite3/sqlite-rembed-0.0.1-alpha.9 sqlite3/sqlite-rembed-source
-	cd sqlite3/sqlite-rembed-source && SQLITE3_INCLUDE_DIR=$(SQLITE3_INCLUDE_DIR) SQLITE3_LIB_DIR=$(SQLITE3_LIB_DIR) SQLITE3_STATIC=1 $(CARGO) build --release --features=sqlite-loadable/static --lib
-	cp sqlite3/sqlite-rembed-source/target/release/libsqlite_rembed.a sqlite3/libsqlite_rembed.a
-
-sqlite-rembed: sqlite3/libsqlite_rembed.a
-
-
 ### clean targets
 
 cleanpart: