Split the Gitea job so graduation does not break CI on the runner

The single rust job ran cargo clippy --workspace, which after graduation pulls
GPUI onto a runner that has neither the X11 development packages nor a measured
disk budget. It would have failed on the next push.

rust-headless gates every push and stays fast. rust-ui installs the native
dependencies, reports df before and after so the runner's actual budget gets
measured, and is continue-on-error until it has run green a few times — a job
that OOMs on every push trains people to ignore CI, which is worse than one that
reports without blocking. The flag comes off on evidence, not on assumption.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -5,7 +5,8 @@ on:
   pull_request:
 
 jobs:
-  rust:
+  # Everything except the GPUI product. Builds in seconds, gates every push.
+  rust-headless:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
@@ -17,11 +18,63 @@ jobs:
           toolchain: 1.94.1
           components: rustfmt, clippy
 
-      - name: Format
-        run: cargo fmt --all --check
+      - name: Cache cargo
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: headless-${{ hashFiles('Cargo.lock') }}
 
-      - name: Lint
-        run: cargo clippy --workspace --all-targets --all-features -- -D warnings
+      - name: Headless checks
+        run: ./scripts/ci.sh --headless
 
-      - name: Test
-        run: cargo test --workspace --all-features
+  # The GPUI product. Kept separate because it pulls a window toolkit, several
+  # hundred extra packages, and a large target directory.
+  #
+  # continue-on-error until this runner's disk, memory, and time budget have
+  # actually been measured against a GPUI build. A job that OOMs on every push
+  # trains people to ignore CI, which is worse than a job that reports and does
+  # not block. Remove the flag once it has run green a few times; do not remove
+  # it by assuming it will.
+  rust-ui:
+    runs-on: ubuntu-latest
+    needs: rust-headless
+    continue-on-error: true
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install pinned Rust toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: 1.94.1
+          components: rustfmt, clippy
+
+      # GPUI's X11 backend links against these. libxkbcommon-x11-dev is the
+      # package scripts/native-libs.sh works around when it is missing.
+      - name: Install native dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y --no-install-recommends \
+            libxkbcommon-x11-dev libxcb1-dev libwayland-dev \
+            libasound2-dev libfontconfig1-dev pkg-config
+
+      - name: Cache cargo
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ui-${{ hashFiles('Cargo.lock') }}
+
+      - name: Report disk before build
+        run: df -h .
+
+      - name: UI checks
+        run: ./scripts/ci.sh --ui
+
+      - name: Report disk after build
+        run: df -h .