ci: Add ccache for faster builds + parallel OTA deployment

Build improvements:
- Enable ccache via IDF_CCACHE_ENABLE=1
- Mount /var/cache/ccache volume for persistent cache
- Show ccache stats after build

Deployment improvements:
- Deploy to all sensors in parallel (max 3)
- Reduced total deploy time from ~2.5min to ~1min

Note: Runner needs /var/cache/ccache directory with write permissions

.gitea/workflows/lint.yml

@@ -23,18 +23,32 @@ jobs:
     runs-on: anvil
     container:
       image: docker.io/espressif/idf:v5.3
+      volumes:
+        - /var/cache/ccache:/ccache
+    env:
+      CCACHE_DIR: /ccache
+      IDF_CCACHE_ENABLE: 1
     steps:
       - name: Checkout
         run: |
           git clone --depth=1 --branch=${{ github.ref_name }} \
             https://oauth2:${{ github.token }}@git.mymx.me/${{ github.repository }}.git .
 
+      - name: Setup ccache
+        run: |
+          apt-get update && apt-get install -y --no-install-recommends ccache
+          ccache --zero-stats
+          ccache --show-config | grep -E "(cache_dir|max_size)"
+
       - name: Build firmware
         run: |
           . /opt/esp/idf/export.sh
           cd get-started/csi_recv_router
           idf.py build
 
+      - name: Show ccache stats
+        run: ccache --show-stats
+
       - name: Show binary size
         run: |
           ls -lh get-started/csi_recv_router/build/*.bin
@@ -57,10 +71,15 @@ jobs:
     container:
       image: docker.io/espressif/idf:v5.3
       options: --network host
+      volumes:
+        - /var/cache/ccache:/ccache
+    env:
+      CCACHE_DIR: /ccache
+      IDF_CCACHE_ENABLE: 1
     steps:
       - name: Install tools
         run: |
-          apt-get update && apt-get install -y --no-install-recommends netcat-openbsd curl jq
+          apt-get update && apt-get install -y --no-install-recommends netcat-openbsd curl jq ccache
 
       - name: Checkout
         run: |
@@ -72,6 +91,7 @@ jobs:
           . /opt/esp/idf/export.sh
           cd get-started/csi_recv_router
           idf.py build
+          ccache --show-stats | head -5
 
       - name: Create release and upload firmware
         env:
@@ -110,8 +130,8 @@ jobs:
       - name: Deploy via OTA
         run: |
           SENSORS="muddy-storm:192.168.129.29 amber-maple:192.168.129.30 hollow-acorn:192.168.129.31"
-          FIRMWARE_PATH="get-started/csi_recv_router/build/csi_recv_router.bin"
           OTA_PORT=8899
+          MAX_PARALLEL=3
 
           # Get runner IP (first non-loopback interface)
           RUNNER_IP=$(hostname -I | awk '{print $1}')
@@ -129,15 +149,34 @@ jobs:
           # Verify server is running
           curl -sI "http://localhost:${OTA_PORT}/csi_recv_router.bin" | head -1
 
-          # Deploy to each sensor
+          # Deploy function
+          deploy_sensor() {
+            NAME="$1"
+            IP="$2"
+            URL="$3"
+            echo "=== Starting OTA on $NAME ($IP) ==="
+            RESPONSE=$(echo "OTA $URL" | nc -u -w 2 "$IP" 5501 2>/dev/null || echo "no response")
+            echo "$NAME: $RESPONSE"
+          }
+
+          # Deploy to all sensors in parallel (max $MAX_PARALLEL)
+          echo "=== Deploying to all sensors in parallel ==="
+          PIDS=""
           for entry in $SENSORS; do
             NAME="${entry%%:*}"
             IP="${entry##*:}"
-            echo "=== Deploying to $NAME ($IP) ==="
-            echo "OTA $FIRMWARE_URL" | nc -u -w 2 "$IP" 5501 || true
-            sleep 45
+            deploy_sensor "$NAME" "$IP" "$FIRMWARE_URL" &
+            PIDS="$PIDS $!"
           done
 
+          # Wait for all OTA commands to be sent
+          for PID in $PIDS; do
+            wait $PID 2>/dev/null || true
+          done
+
+          echo "=== OTA commands sent, waiting for devices to update (60s) ==="
+          sleep 60
+
           # Stop HTTP server
           kill $HTTP_PID 2>/dev/null || true