feat: add reusable issue submitter detector

.github/scripts/find_addon_submitter.sh

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+mapping_file="${1:-.github/addon_submitters.json}"
+output_file="${GITHUB_OUTPUT:-/dev/stdout}"
+
+if [[ ! -f "$mapping_file" ]]; then
+    echo "Mapping file not found: $mapping_file" >&2
+    exit 1
+fi
+
+normalize() {
+    tr '[:upper:]' '[:lower:]' |
+        sed -E 's/[^a-z0-9]+/ /g; s/^ +//; s/ +$//; s/ +/ /g'
+}
+
+text="$(printf '%s %s' "${ISSUE_TITLE:-}" "${ISSUE_BODY:-}" | normalize)"
+text=" $text "
+matches='[]'
+
+while IFS= read -r addon; do
+    [[ -z "$addon" ]] && continue
+
+    submitter="$(jq -r --arg addon "$addon" '.[$addon] // empty' "$mapping_file")"
+    [[ -z "$submitter" ]] && continue
+
+    normalized_addon="$(printf '%s' "$addon" | normalize)"
+    [[ -z "$normalized_addon" ]] && continue
+
+    if [[ "$text" == *" $normalized_addon "* ]]; then
+        matches="$(
+            jq -c \
+                --arg addon "$addon" \
+                --arg submitter "$submitter" \
+                '. + [{addon: $addon, submitter: $submitter}]' <<< "$matches"
+        )"
+    fi
+done < <(jq -r 'keys[]' "$mapping_file")
+
+matched=false
+addon=''
+submitter=''
+
+if [[ "$(jq 'length' <<< "$matches")" -gt 0 ]]; then
+    matched=true
+    addon="$(jq -r '.[0].addon' <<< "$matches")"
+    submitter="$(jq -r '.[0].submitter' <<< "$matches")"
+fi
+
+{
+    echo "matched=$matched"
+    echo "addon=$addon"
+    echo "submitter=$submitter"
+    echo "matches_json=$matches"
+} >> "$output_file"