Add gitcompare workflow & commit_hunter.sh script

.github/scripts/commit_hunter.sh

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+#!/usr/bin/env bash
+#
+# .github/scripts/commit_hunter.sh
+#
+# Arg1: the full GitHub comment body
+#
+set -euo pipefail
+
+COMMENT="$1"
+
+# 1) Remove leading /gitcompare line
+BODY="${COMMENT#*\/gitcompare}"
+
+# 2) Normalize Windows line endings
+BODY="${BODY//$'\r'/}"
+
+# 3) Split on the first line containing only dashes (allowing spaces)
+#    We use awk for robustness
+GOOD=$(printf '%s\n' "$BODY" \
+  | awk 'BEGIN{sep="---"} 
+         $0 ~ "^[[:space:]]*" sep "[[:space:]]*$" { exit } 
+         {print}')
+
+BAD=$(printf '%s\n' "$BODY" \
+  | awk 'BEGIN{sep="---"} 
+         $0 ~ "^[[:space:]]*" sep "[[:space:]]*$" {found=1; next} 
+         found {print}')
+
+# 4) Trim blank lines
+trim() { printf '%s\n' "$1" | sed '/^[[:space:]]*$/d'; }
+GOOD=$(trim "$GOOD")
+BAD=$(trim "$BAD")
+
+# >>> Now you have two variables, GOOD and BAD, containing exactly what you need.
+# For example:
+echo "Comparing these SHAs from GOOD:"
+echo "$GOOD" | grep -oE '[0-9a-f]{7,}' 
+echo
+echo "…against BAD:"
+echo "$BAD"  | grep -oE '[0-9a-f]{7,}'
+echo
+
+# 5) Call your existing compare routine.
+#    Pass GOOD and BAD as multi-line arguments:
+./commit_hunter_core.sh "$GOOD" "$BAD"

.github/workflows/gitcompare.yml

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+# .github/workflows/gitcompare.yml
+name: GitCompare by Comment
+
+on:
+  issue_comment:
+    types: [created]
+
+jobs:
+  comment_trigger:
+    runs-on: ubuntu-latest
+    if: contains(github.event.comment.body, '/gitcompare')
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Run commit_hunter.sh over full comment
+        env:
+          COMMENT_BODY: ${{ github.event.comment.body }}
+        run: |
+          chmod +x .github/scripts/commit_hunter.sh
+          ./.github/scripts/commit_hunter.sh "$COMMENT_BODY"