fix(mosaic): harden gitea pr wrapper metadata

packages/mosaic/framework/tools/git/pr-metadata.sh

@@ -5,6 +5,7 @@
 set -e
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck disable=SC1091
 source "$SCRIPT_DIR/detect-platform.sh"
 
 # Parse arguments
@@ -55,39 +56,51 @@ if [[ "$PLATFORM" == "github" ]]; then
 elif [[ "$PLATFORM" == "gitea" ]]; then
     OWNER=$(get_repo_owner)
     REPO=$(get_repo_name)
-    REMOTE_URL=$(git remote get-url origin 2>/dev/null)
-
-    # Extract host from remote URL
-    if [[ "$REMOTE_URL" == https://* ]]; then
-        HOST=$(echo "$REMOTE_URL" | sed -E 's|https://([^/]+)/.*|\1|')
-    elif [[ "$REMOTE_URL" == git@* ]]; then
-        HOST=$(echo "$REMOTE_URL" | sed -E 's|git@([^:]+):.*|\1|')
-    else
+    HOST=$(get_remote_host) || {
         echo "Error: Cannot determine host from remote URL" >&2
         exit 1
-    fi
+    }
 
     API_URL="https://${HOST}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}"
 
     GITEA_API_TOKEN=$(get_gitea_token "$HOST" || true)
 
+    RESPONSE_FILE=$(mktemp)
+    trap 'rm -f "$RESPONSE_FILE"' EXIT
     if [[ -n "$GITEA_API_TOKEN" ]]; then
-        RAW=$(curl -sS -H "Authorization: token $GITEA_API_TOKEN" "$API_URL")
+        HTTP_CODE=$(curl -sS -H "Authorization: token $GITEA_API_TOKEN" -o "$RESPONSE_FILE" -w '%{http_code}' "$API_URL")
     else
-        RAW=$(curl -sS "$API_URL")
+        HTTP_CODE=$(curl -sS -o "$RESPONSE_FILE" -w '%{http_code}' "$API_URL")
+    fi
+    RAW=$(cat "$RESPONSE_FILE")
+    rm -f "$RESPONSE_FILE"
+    trap - EXIT
+
+    if [[ ! "$HTTP_CODE" =~ ^2 ]]; then
+        echo "Error: Gitea PR metadata request failed for ${OWNER}/${REPO}#${PR_NUMBER} (HTTP ${HTTP_CODE})" >&2
+        exit 1
     fi
 
     # Normalize Gitea response to match our expected schema
     METADATA=$(echo "$RAW" | python3 -c "
 import json, sys
 data = json.load(sys.stdin)
+if 'message' in data and not data.get('number'):
+    raise SystemExit('Error: Gitea PR metadata response did not contain PR data')
+head = data.get('head') or {}
+head_ref = head.get('ref') or ''
+head_label = head.get('label') or ''
+# Gitea can report closed/merged PR heads as refs/pull/<n>/head; callers need
+# the source branch name equivalent to GitHub headRefName, so prefer label then.
+if head_ref.startswith('refs/pull/') and head_label:
+    head_ref = head_label
 normalized = {
     'number': data.get('number'),
     'title': data.get('title'),
     'body': data.get('body', ''),
     'state': data.get('state'),
     'author': data.get('user', {}).get('login', ''),
-    'headRefName': data.get('head', {}).get('ref', ''),
+    'headRefName': head_ref,
     'baseRefName': data.get('base', {}).get('ref', ''),
     'labels': [l.get('name', '') for l in data.get('labels', [])],
     'assignees': [a.get('login', '') for a in data.get('assignees', [])],