chore: remove fuzzing from nightly ci (#1564)

This keeps failing and I don't think the right way to
do fuzzing is in a job like this anyway so removing.

.github/workflows/fuzz.yml

@@ -1,149 +0,0 @@
-name: Fuzz
-
-on:
-  schedule:
-    - cron: "0 2 * * *" # Daily at 2am UTC
-  workflow_dispatch: # Allow manual trigger
-
-# Cancel previous runs on same ref
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-env:
-  CARGO_TERM_COLOR: always
-
-permissions:
-  contents: read
-
-jobs:
-  # Group A: Runs on Machine A (fuzz-a labeled runners)
-  fuzz-group-a:
-    name: "Fuzz A: ${{ matrix.target }}"
-    runs-on: [self-hosted, fuzz-a]
-    timeout-minutes: 90
-    strategy:
-      fail-fast: false
-      max-parallel: 4
-      matrix:
-        target:
-          - fuzz_token
-          - fuzz_payment_request
-          - fuzz_secret
-          - fuzz_mint_url
-          - fuzz_keyset_id
-          - fuzz_proof
-          - fuzz_blind_signature
-          - fuzz_amount
-          - fuzz_dleq
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Setup Cachix
-        uses: cachix/cachix-action@v16
-        with:
-          name: cashudevkit
-          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
-          useDaemon: false
-        continue-on-error: true
-      - name: Fuzz ${{ matrix.target }}
-        run: nix develop -i -L .#nightly --command just fuzz ${{ matrix.target }} 3600 4
-
-      - name: Create Security Advisory on crash
-        if: failure()
-        env:
-          GH_TOKEN: ${{ secrets.SECURITY_ADVISORY_TOKEN }}
-        run: |
-          TARGET="${{ matrix.target }}"
-          ARTIFACT_DIR="fuzz/artifacts/$TARGET"
-          
-          if [ -d "$ARTIFACT_DIR" ] && [ "$(ls -A $ARTIFACT_DIR 2>/dev/null)" ]; then
-            ARTIFACT_DATA=$(tar czf - "$ARTIFACT_DIR" | base64 -w0)
-            
-            gh api repos/${{ github.repository }}/security-advisories \
-              --method POST \
-              -f summary="[Fuzzing] Crash in $TARGET" \
-              -f description="Automated fuzzing found a crash in \`$TARGET\`.
-
-          **Workflow Run:** ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
-          **Commit:** ${{ github.sha }}
-
-          ## Crash Artifact (base64 tar.gz)
-
-          \`\`\`
-          $ARTIFACT_DATA
-          \`\`\`
-
-          ## To reproduce locally
-
-          1. Decode: \`echo '<base64-data>' | base64 -d > crash.tar.gz && tar xzf crash.tar.gz\`
-          2. Run: \`cargo fuzz run $TARGET fuzz/artifacts/$TARGET/<crash-file>\`" \
-              -f severity="low" \
-              -f "vulnerabilities[0][package][ecosystem]=other" \
-              -f "vulnerabilities[0][package][name]=cdk"
-          fi
-
-  # Group B: Runs on Machine B (fuzz-b labeled runners)
-  fuzz-group-b:
-    name: "Fuzz B: ${{ matrix.target }}"
-    runs-on: [self-hosted, fuzz-b]
-    timeout-minutes: 90
-    strategy:
-      fail-fast: false
-      max-parallel: 4
-      matrix:
-        target:
-          - fuzz_currency_unit
-          - fuzz_spending_conditions
-          - fuzz_htlc_witness
-          - fuzz_token_raw_bytes
-          - fuzz_p2pk_witness
-          - fuzz_witness
-          - fuzz_swap_request
-          - fuzz_melt_request
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-      - name: Setup Cachix
-        uses: cachix/cachix-action@v16
-        with:
-          name: cashudevkit
-          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
-          useDaemon: false
-        continue-on-error: true
-      - name: Fuzz ${{ matrix.target }}
-        run: nix develop -i -L .#nightly --command just fuzz ${{ matrix.target }} 3600 4
-
-      - name: Create Security Advisory on crash
-        if: failure()
-        env:
-          GH_TOKEN: ${{ secrets.SECURITY_ADVISORY_TOKEN }}
-        run: |
-          TARGET="${{ matrix.target }}"
-          ARTIFACT_DIR="fuzz/artifacts/$TARGET"
-          
-          if [ -d "$ARTIFACT_DIR" ] && [ "$(ls -A $ARTIFACT_DIR 2>/dev/null)" ]; then
-            ARTIFACT_DATA=$(tar czf - "$ARTIFACT_DIR" | base64 -w0)
-            
-            gh api repos/${{ github.repository }}/security-advisories \
-              --method POST \
-              -f summary="[Fuzzing] Crash in $TARGET" \
-              -f description="Automated fuzzing found a crash in \`$TARGET\`.
-
-          **Workflow Run:** ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
-          **Commit:** ${{ github.sha }}
-
-          ## Crash Artifact (base64 tar.gz)
-
-          \`\`\`
-          $ARTIFACT_DATA
-          \`\`\`
-
-          ## To reproduce locally
-
-          1. Decode: \`echo '<base64-data>' | base64 -d > crash.tar.gz && tar xzf crash.tar.gz\`
-          2. Run: \`cargo fuzz run $TARGET fuzz/artifacts/$TARGET/<crash-file>\`" \
-              -f severity="low" \
-              -f "vulnerabilities[0][package][ecosystem]=other" \
-              -f "vulnerabilities[0][package][name]=cdk"
-          fi