Revert "build: root .cargo/config.toml enables the real OCIO bridge workspace-wide"

Machine-specific Homebrew paths do not belong in the repo; set
OCIO_RS_ENABLE_REAL/OCIO_INSTALL_DIR/OCIO_RS_LINK locally instead.

.cargo/config.toml

@@ -1,31 +0,0 @@
-# Oak Video Editor - Non-Linear Video Editor
-# Copyright (C) 2026 Oak Team
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-# `ocio-sys` (the FFI layer behind `ocio-rs`) does not probe the system for
-# OpenColorIO on its own: with no configuration it builds a *stub* bridge
-# whose calls all fail. These environment variables make it link the real
-# Homebrew OpenColorIO dylib:
-#
-#   OCIO_RS_ENABLE_REAL  - opt into the real (non-stub) bridge
-#   OCIO_INSTALL_DIR     - prefix whose include/ and lib/ hold OpenColorIO
-#   OCIO_RS_LINK         - Homebrew ships a dylib, so link dynamically
-#
-# See README.md "Build & test" for the bundled alternative.
-
-[env]
-OCIO_RS_ENABLE_REAL = "1"
-OCIO_INSTALL_DIR = "/opt/homebrew/opt/opencolorio"
-OCIO_RS_LINK = "dynamic"