Remove Gleam from CI workflow

- Remove Gleam setup from GitHub Actions workflow
- Remove mix_gleam installation step
- Remove Gleam package caching
- Remove mix gleam_compile step

This completes the removal of all Gleam-related code and tooling.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/elixir.yaml

@@ -48,37 +48,17 @@ jobs:
         otp: ["27.3.4"]
         elixir: ["1.18.4"]
     steps:
-      # Step: Setup Elixir + Erlang + Gleam using erlef/setup-beam
-      - name: Set up Elixir, Erlang, and Gleam
+      # Step: Setup Elixir + Erlang using erlef/setup-beam
+      - name: Set up Elixir and Erlang
         uses: erlef/setup-beam@v1
         with:
           otp-version: ${{matrix.otp}}
           elixir-version: ${{matrix.elixir}}
-          gleam-version: "1.5.1"
 
       # Step: Check out the code.
       - name: Checkout code
         uses: actions/checkout@v4
 
-      # Step: Install mix_gleam archive
-      - name: Install mix_gleam
-        run: mix archive.install hex mix_gleam 0.6.2 --force
-
-      # Step: Cache Gleam packages
-      - name: Cache Gleam packages
-        id: cache-gleam
-        uses: actions/cache@v4
-        env:
-          cache-name: cache-gleam-packages
-        with:
-          path: |
-            build
-            ~/.cache/gleam
-          key: ${{ runner.os }}-gleam-${{ env.cache-name }}-${{ hashFiles('**/gleam.toml') }}
-          restore-keys: |
-            ${{ runner.os }}-gleam-${{ env.cache-name }}-
-            ${{ runner.os }}-gleam-
-
       # Step: Define how to cache deps. Restores existing cache if present.
       - name: Cache deps
         id: cache-deps
@@ -124,10 +104,6 @@ jobs:
       - name: Install dependencies
         run: mix deps.get
 
-      # Step: Compile Gleam code first
-      - name: Compile Gleam code
-        run: mix gleam_compile
-
       # Step: Compile the project treating any warnings as errors.
       # Customize this step if a different behavior is desired.
       - name: Compiles without warnings