feat: summarize changes with AI by AI (WIP)

.github/workflows/qgs-ai-summary.yml

@@ -0,0 +1,95 @@
+name: qgs-ai-summary
+
+# Post a concise, human-readable summary of the real changes to QGIS .qgs
+# project files on a PR. scripts/qgs-diff.py builds a churn-free diff of the
+# changed files; GitHub Models turns it into per-file bullet points; the result
+# is posted as a single self-updating PR comment. Nothing derived is committed.
+
+on:
+  pull_request:
+    paths:
+      - '**/*.qgs'
+
+permissions:
+  contents: read
+  pull-requests: write
+  models: read
+
+
+concurrency:
+  group: qgs-ai-summary-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  summarise:
+    runs-on: ubuntu-latest
+    env:
+      MODEL: openai/gpt-4.1
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 0
+
+      - name: Build churn-free diff
+        id: diff
+        run: |
+          python3 scripts/qgs-diff.py diff --base "${{ github.base_ref }}" > diff.txt
+          [ -s diff.txt ] && echo "changed=1" >> "$GITHUB_OUTPUT" || echo "changed=0" >> "$GITHUB_OUTPUT"
+
+      - name: Summarise with GitHub Models
+        id: ai
+        if: steps.diff.outputs.changed == '1'
+        uses: actions/ai-inference@v2
+        with:
+          model: ${{ env.MODEL }}
+          max-completion-tokens: 3000
+          prompt-file: diff.txt
+          system-prompt: |
+            You are reviewing changes to QGIS .qgs project files for a pull
+            request. You are given a unified diff per file; QGIS session churn
+            has already been stripped, so ignore residual noise (reordered
+            attributes, internal ids, emptied values).
+
+            Write a concise GitHub-flavored-markdown summary:
+            - Group by file under a "### <path>" heading matching the diff.
+            - Short bullets, substantive changes only: layers added / removed /
+              renamed / reordered, symbology, labelling, scale ranges, print
+              layouts, project CRS, variables, map themes, expressions, data
+              sources. Name the actual layers, properties and values.
+            - Do not restate raw XML, omit unchanged files, never invent changes.
+            - Output only the per-file sections, no preamble or conclusion.
+
+      - name: Post sticky PR comment
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          PR: ${{ github.event.pull_request.number }}
+          CHANGED: ${{ steps.diff.outputs.changed }}
+          AI_RESPONSE: ${{ steps.ai.outputs.response }}
+          MODEL: ${{ env.MODEL }}
+        run: |
+          set -euo pipefail
+          MARKER='<!-- qgs-ai-summary -->'
+          {
+            echo "$MARKER"
+            echo "## 🗺️ QGIS project change summary"
+            echo
+            if [ "$CHANGED" = "1" ]; then
+              printf '%s\n' "$AI_RESPONSE"
+              echo
+              echo "<sub>Generated by \`$MODEL\` via GitHub Models from a churn-free diff - verify against the file diff.</sub>"
+            else
+              echo "_No substantive QGIS project changes detected - only QGIS session churn._"
+            fi
+          } > comment.md
+
+          id=$(gh api "repos/$REPO/issues/$PR/comments" --paginate \
+                 --jq ".[] | select(.body | contains(\"$MARKER\")) | .id" | head -n1)
+          if [ -n "$id" ]; then
+            gh api -X PATCH "repos/$REPO/issues/comments/$id" -F body=@comment.md >/dev/null
+            echo "updated comment $id"
+          else
+            gh api -X POST "repos/$REPO/issues/$PR/comments" -F body=@comment.md >/dev/null
+            echo "created comment"
+          fi