feat: add firmware stats extraction and PR commenting

.github/workflows/ci.yml

@@ -4,6 +4,10 @@ name: CI
     branches: [master]
   pull_request:
 
+permissions:
+  contents: read
+  pull-requests: write
+
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -34,4 +38,51 @@ jobs:
         run: PATH="/usr/lib/llvm-21/bin:$PATH" ./bin/clang-format-fix && git diff --exit-code || (echo "Please run 'bin/clang-format-fix' to fix formatting issues" && exit 1)
 
       - name: Build CrossPoint
-        run: pio run
+        run: |
+          set -euo pipefail
+          pio run | tee pio.log
+
+      - name: Extract firmware stats
+        id: fw_stats
+        run: |
+          set -euo pipefail
+          ram_line="$(grep -E "RAM:\\s" -m1 pio.log || true)"
+          flash_line="$(grep -E "Flash:\\s" -m1 pio.log || true)"
+          echo "ram_line=${ram_line}" >> "$GITHUB_OUTPUT"
+          echo "flash_line=${flash_line}" >> "$GITHUB_OUTPUT"
+          {
+            echo "## Firmware build stats"
+            if [ -n "$ram_line" ]; then echo "- ${ram_line}"; else echo "- RAM: not found"; fi
+            if [ -n "$flash_line" ]; then echo "- ${flash_line}"; else echo "- Flash: not found"; fi
+          } >> "$GITHUB_STEP_SUMMARY"
+
+      - name: Comment PR with firmware stats
+        if: github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork == false
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const marker = '<!-- firmware-stats -->';
+            const ram = `${{ steps.fw_stats.outputs.ram_line }}`.trim();
+            const flash = `${{ steps.fw_stats.outputs.flash_line }}`.trim();
+            const body = `${marker}\n**Firmware build stats**\n\n- ${ram || 'RAM: not found'}\n- ${flash || 'Flash: not found'}`;
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+            });
+            const existing = comments.find((comment) => comment.body && comment.body.includes(marker));
+            if (existing) {
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existing.id,
+                body,
+              });
+            } else {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body,
+              });
+            }