chore(build): use one Rust toolchain for all FFI builds

Bump the pinned Rust toolchain to 1.95.0 and drop the separate stable channel
that only the Vortex FFI build used. The Vortex cargo invocation now selects
the pinned toolchain explicitly, which overrides the rust-toolchain.toml
shipped inside the Vortex archive, so Lance, Mosaic, Vortex and the full-text
index all build with a single toolchain.

Author: zhouyc-ali

ci/scripts/setup_rust.sh

@@ -26,8 +26,8 @@
 set -eux
 
 RUSTUP_VERSION=${RUSTUP_VERSION:-1.29.0}
-# 1.90.0 is the minimum required by paimon-full-text 0.1.0 (rust-version in its Cargo.toml).
-RUST_VERSION=${RUST_VERSION:-1.90.0}
+# Keep in sync with PAIMON_RUST_TOOLCHAIN in cmake_modules/ThirdpartyToolchain.cmake.
+RUST_VERSION=${RUST_VERSION:-1.95.0}
 CBINDGEN_VERSION=${CBINDGEN_VERSION:-0.29.2}
 PROTOC_VERSION=27.4
 
@@ -76,11 +76,6 @@ if ! command -v protoc >/dev/null 2>&1 || \
     echo "${protoc_home}/bin" >> "${GITHUB_PATH:-/dev/null}" || true
 fi
 
-# Vortex's FFI build pins rust-version >= 1.95 and is invoked with RUSTUP_TOOLCHAIN=stable (see
-# cmake_modules/ThirdpartyToolchain.cmake). Install the stable channel alongside the pinned default
-# so Vortex builds with it while Lance, Mosaic and tantivy-fts keep using the default toolchain.
-rustup toolchain install stable --profile minimal
-
 # cbindgen is used by the crate's build.rs to emit the C header that the
 # C++ side includes. Corrosion will also run cbindgen at CMake configure
 # time; both paths need it available.

cmake_modules/ThirdpartyToolchain.cmake

@@ -1499,6 +1499,11 @@ macro(build_vortex)
     # neither of which can go through paimon's filesystem. `callback_io.rs` adds an entry point
     # backed by host callbacks; it is maintained in this repository and injected into the Vortex
     # source tree, and the patch only declares the module.
+    # Keep in sync with RUST_VERSION in ci/scripts/setup_rust.sh; it overrides the
+    # rust-toolchain.toml shipped inside the Vortex archive.
+    set(PAIMON_RUST_TOOLCHAIN
+        "1.95.0"
+        CACHE STRING "Rust toolchain used by the Vortex FFI build.")
     set(VORTEX_PATCH_FILE "${CMAKE_CURRENT_LIST_DIR}/vortex.diff")
     set(VORTEX_CALLBACK_IO_SRC
         "${CMAKE_SOURCE_DIR}/crates/vortex_callback_io/callback_io.rs")
@@ -1533,8 +1538,8 @@ macro(build_vortex)
                                       "${VORTEX_CALLBACK_IO_SRC}"
                                       "<SOURCE_DIR>/vortex-ffi/src/callback_io.rs"
                         COMMAND ${CMAKE_COMMAND} -E env "FLATC=${VORTEX_FLATC}"
-                                "RUSTUP_TOOLCHAIN=stable" "CC=${CMAKE_C_COMPILER}"
-                                "CXX=${CMAKE_CXX_COMPILER}"
+                                "RUSTUP_TOOLCHAIN=${PAIMON_RUST_TOOLCHAIN}"
+                                "CC=${CMAKE_C_COMPILER}" "CXX=${CMAKE_CXX_COMPILER}"
                                 "CARGO_TARGET_DIR=${VORTEX_CARGO_TARGET_DIR}"
                                 "RUSTFLAGS=-Crelocation-model=pic"
                                 ${PAIMON_CARGO_EXECUTABLE} rustc --locked --package