ci: rely on release profile LTO settings

.github/workflows/rust-ci-full.yml

@@ -162,8 +162,6 @@ jobs:
       USE_SCCACHE: ${{ (startsWith(matrix.runner, 'windows') || (matrix.runner == 'macos-15-xlarge' && matrix.target == 'x86_64-apple-darwin')) && 'false' || 'true' }}
       CARGO_INCREMENTAL: "0"
       SCCACHE_CACHE_SIZE: 10G
-      # In rust-ci, representative release-profile checks use thin LTO for faster feedback.
-      CARGO_PROFILE_RELEASE_LTO: ${{ matrix.profile == 'release' && 'thin' || 'fat' }}
 
     strategy:
       fail-fast: false

.github/workflows/rust-release-windows.yml

@@ -2,10 +2,6 @@ name: rust-release-windows
 
 on:
   workflow_call:
-    inputs:
-      release-lto:
-        required: true
-        type: string
     secrets:
       AZURE_TRUSTED_SIGNING_CLIENT_ID:
         required: true
@@ -24,17 +20,14 @@ jobs:
   build-windows-binaries:
     name: Build Windows binaries - ${{ matrix.runner }} - ${{ matrix.target }} - ${{ matrix.bundle }}
     runs-on: ${{ matrix.runs_on }}
-    # Windows release builds can exceed an hour on fat-LTO mainline releases,
-    # so keep the timeout aligned with the top-level release build headroom.
+    # Windows release builds can exceed an hour, so keep the timeout aligned
+    # with the top-level release build headroom.
     timeout-minutes: 90
     permissions:
       contents: read
     defaults:
       run:
         working-directory: codex-rs
-    env:
-      CARGO_PROFILE_RELEASE_LTO: ${{ inputs.release-lto }}
-
     strategy:
       fail-fast: false
       matrix:

.github/workflows/rust-release.yml

@@ -146,9 +146,6 @@ jobs:
       run:
         working-directory: codex-rs
     env:
-      # 2026-03-04: temporarily change releases to use thin LTO because
-      # Ubuntu ARM is timing out at 60 minutes.
-      CARGO_PROFILE_RELEASE_LTO: ${{ contains(github.ref_name, '-alpha') && 'thin' || 'thin' }}
       SIGN_MACOS: ${{ github.event_name != 'workflow_dispatch' }}
 
     strategy:
@@ -371,7 +368,6 @@ jobs:
           for binary in ${{ matrix.binaries }}; do
             build_args+=(--bin "$binary")
           done
-          echo "CARGO_PROFILE_RELEASE_LTO: ${CARGO_PROFILE_RELEASE_LTO}"
           cargo build --target ${{ matrix.target }} --release --timings "${build_args[@]}"
 
       - name: Upload Cargo timings
@@ -873,8 +869,6 @@ jobs:
     if: ${{ github.event_name != 'workflow_dispatch' || inputs.release_mode != 'promote_signed' }}
     needs: tag-check
     uses: ./.github/workflows/rust-release-windows.yml
-    with:
-      release-lto: ${{ contains(github.ref_name, '-alpha') && 'thin' || 'fat' }}
     secrets: inherit
 
   argument-comment-lint-release-assets: