Fix build size regex patterns in CI workflow

Updated regex patterns to correctly extract Flash and RAM percentages
from PlatformIO build output using Perl-compatible regex (grep -oP).

Changes:
- Flash regex: grep -oP 'Flash:\s+\[.*?\]\s+\K[0-9.]+%'
- RAM regex: grep -oP 'RAM:\s+\[.*?\]\s+\K[0-9.]+%'

The new patterns correctly handle the actual output format:
"RAM:   [==        ]  15.8% (used 51788 bytes from 327680 bytes)"
"Flash: [========  ]  77.7% (used 1018701 bytes from 1310720 bytes)"

Previous patterns were failing to extract values properly.
Tested and verified working with current build output.

Author: arunkumar-mourougappane

.github/workflows/build.yml

@@ -141,8 +141,8 @@ jobs:
 
     - name: Get current build size
       run: |
-        CURRENT_FLASH=$(pio run --environment esp32dev 2>&1 | grep -o "Flash: \[[^]]*\] [0-9.]*%" | grep -o "[0-9.]*%" | tail -1)
-        CURRENT_RAM=$(pio run --environment esp32dev 2>&1 | grep -o "RAM: \[[^]]*\] [0-9.]*%" | grep -o "[0-9.]*%" | tail -1)
+        CURRENT_FLASH=$(pio run --environment esp32dev 2>&1 | grep -oP 'Flash:\s+\[.*?\]\s+\K[0-9.]+%' | tail -1)
+        CURRENT_RAM=$(pio run --environment esp32dev 2>&1 | grep -oP 'RAM:\s+\[.*?\]\s+\K[0-9.]+%' | tail -1)
         echo "CURRENT_FLASH=${CURRENT_FLASH}" >> $GITHUB_ENV
         echo "CURRENT_RAM=${CURRENT_RAM}" >> $GITHUB_ENV
     
@@ -156,8 +156,8 @@ jobs:
 
     - name: Get base build size
       run: |
-        BASE_FLASH=$(pio run --environment esp32dev 2>&1 | grep -o "Flash: \[[^]]*\] [0-9.]*%" | grep -o "[0-9.]*%" | tail -1)
-        BASE_RAM=$(pio run --environment esp32dev 2>&1 | grep -o "RAM: \[[^]]*\] [0-9.]*%" | grep -o "[0-9.]*%" | tail -1)
+        BASE_FLASH=$(pio run --environment esp32dev 2>&1 | grep -oP 'Flash:\s+\[.*?\]\s+\K[0-9.]+%' | tail -1)
+        BASE_RAM=$(pio run --environment esp32dev 2>&1 | grep -oP 'RAM:\s+\[.*?\]\s+\K[0-9.]+%' | tail -1)
         echo "BASE_FLASH=${BASE_FLASH}" >> $GITHUB_ENV
         echo "BASE_RAM=${BASE_RAM}" >> $GITHUB_ENV