feat(l2): add support for Pico backend

.github/workflows/pr-main_l2_prover.yaml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        backend: ["sp1", "risc0", "zisk", "openvm"]
+        backend: ["sp1", "risc0", "zisk", "openvm", "pico"]
     steps:
       - name: Checkout sources
         uses: actions/checkout@v4
@@ -49,6 +49,7 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           SETUP_KEY: none
+          ZISK_VERSION: 0.14.0
         run: |
           sudo apt-get update
           sudo apt-get install -y xz-utils jq curl build-essential qemu-system libomp-dev libgmp-dev nlohmann-json3-dev protobuf-compiler uuid-dev libgrpc++-dev libsecp256k1-dev libsodium-dev libpqxx-dev nasm libopenmpi-dev openmpi-bin openmpi-common libclang-dev clang gcc-riscv64-unknown-elf
@@ -64,13 +65,23 @@ jobs:
           rustup component add rust-src --toolchain nightly-2025-02-14
           cargo +1.86 install --locked --git https://github.com/openvm-org/openvm.git --tag v1.4.1 cargo-openvm
 
+      - name: Pico toolchain install
+        if: matrix.backend == 'pico'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          rustup install nightly-2025-08-04
+          rustup component add rust-src --toolchain nightly-2025-08-04
+          rustup component add clippy --toolchain nightly-2025-08-04
+          cargo +nightly-2025-08-04 install --git https://github.com/brevis-network/pico --tag v1.1.9 pico-cli
+
       - name: Check ${{ matrix.backend }} backend
         run: |
-          cargo check -r -p ethrex-prover -F "${{ matrix.backend }},ci"
+          cargo ${{ matrix.backend == 'pico' && '+nightly-2025-08-04' || '' }} check -r -p ethrex-prover -F "${{ matrix.backend }},ci"
 
       - name: Clippy ${{ matrix.backend }} backend
         run: |
-          cargo clippy -r -p ethrex-prover --all-targets -F "${{ matrix.backend }},ci"
+          cargo ${{ matrix.backend == 'pico' && '+nightly-2025-08-04' || '' }} clippy -r -p ethrex-prover --all-targets -F "${{ matrix.backend }},ci"
 
       - name: Check ${{ matrix.backend }} Cargo.lock modified but not committed
         run: |

.github/workflows/tag_release.yaml

@@ -161,6 +161,7 @@ jobs:
           - risc0
           - zisk
           - openvm
+          - pico
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -207,9 +208,18 @@ jobs:
           rustup component add rust-src --toolchain nightly-2025-02-14
           cargo +1.86 install --locked --git https://github.com/openvm-org/openvm.git --tag v1.4.1 cargo-openvm
 
+      - name: Install Pico
+        if: ${{ matrix.zkvm == 'pico' }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          rustup install nightly-2025-08-04
+          rustup component add rust-src --toolchain nightly-2025-08-04
+          cargo +nightly-2025-08-04 install --git https://github.com/brevis-network/pico --tag v1.1.9 pico-cli
+
       - name: Build ethrex elf - ${{ matrix.zkvm }}
         run: |
-          cargo build --release --package guest_program --features "${{ matrix.zkvm }},ci"
+          cargo ${{ matrix.zkvm == 'pico' && '+nightly-2025-08-04' || '' }} build --release --package guest_program --features "${{ matrix.zkvm }},ci"
           mkdir -p ${{ matrix.zkvm }}_verification_keys
           if [ "${{ matrix.zkvm }}" = "sp1" ]; then
             mv crates/l2/prover/src/guest_program/src/${{ matrix.zkvm }}/out/riscv32im-succinct-zkvm-elf ethrex-riscv32im-${{ matrix.zkvm }}-elf-${{ github.ref_name }}
@@ -226,6 +236,9 @@ jobs:
           elif [ "${{ matrix.zkvm }}" = "openvm" ]; then
             mv crates/l2/prover/src/guest_program/src/${{ matrix.zkvm }}/out/riscv32im-openvm-elf ethrex-riscv32im-${{ matrix.zkvm }}-elf-${{ github.ref_name}}
             echo "ELF_ARTIFACT=ethrex-riscv32im-${{ matrix.zkvm }}-elf-${{ github.ref_name }}" >> $GITHUB_ENV
+          elif [ "${{ matrix.zkvm }}" = "pico" ]; then
+            mv crates/l2/prover/src/guest_program/src/${{ matrix.zkvm }}/out/riscv32im-pico-zkvm-elf ethrex-riscv32im-${{ matrix.zkvm }}-elf-${{ github.ref_name}}
+            echo "ELF_ARTIFACT=ethrex-riscv32im-${{ matrix.zkvm }}-elf-${{ github.ref_name }}" >> $GITHUB_ENV
           fi
 
       - name: Upload ethrex guest elf artifact - ${{ matrix.zkvm }}
@@ -283,6 +296,12 @@ jobs:
           name: ethrex-riscv32im-openvm-elf-${{ github.ref_name }}
           path: ethrex_guests/openvm/
 
+      - name: Download Pico elf artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: ethrex-riscv32im-pico-elf-${{ github.ref_name }}
+          path: ethrex_guests/pico/
+
       - name: Archive ethrex guests
         run: |
           cd ethrex_guests/