fix(shell): address shellcheck warnings, standardize error handling, add retry logic

- Fix shellcheck SC2155 (separate variable assignment from declaration)
- Replace ! bool && bool pattern with [ "$bool" = true ] && [ "$bool2" = true ]
- Add retry logic for git clone with configurable attempts
- Add retry logic for opencode session fork
- Add NETWORK_RETRY_ATTEMPTS and NETWORK_RETRY_DELAY_SECONDS config vars
- Add retry_with_backoff helper function in kugetsu-config.sh
- Replace subshell cd with git -C for safer directory handling

skills/kugetsu/scripts/kugetsu-config.sh

@@ -26,6 +26,9 @@ QUEUE_DAEMON_INTERVAL_MINUTES="${QUEUE_DAEMON_INTERVAL_MINUTES:-5}"
 QUEUE_CLEANUP_AGE_DAYS="${QUEUE_CLEANUP_AGE_DAYS:-7}"
 TASK_TIMEOUT_HOURS="${TASK_TIMEOUT_HOURS:-1}"
 
+NETWORK_RETRY_ATTEMPTS="${NETWORK_RETRY_ATTEMPTS:-3}"
+NETWORK_RETRY_DELAY_SECONDS="${NETWORK_RETRY_DELAY_SECONDS:-5}"
+
 # Load user config overrides (~/.kugetsu/config)
 if [ -f "$KUGETSU_DIR/config" ]; then
     source "$KUGETSU_DIR/config"
@@ -87,3 +90,24 @@ set_debug_mode() {
     
     echo "${filtered_args[@]}"
 }
+
+retry_with_backoff() {
+    local max_attempts="${1:-$NETWORK_RETRY_ATTEMPTS}"
+    local delay_seconds="${2:-$NETWORK_RETRY_DELAY_SECONDS}"
+    local command="$3"
+    local remaining_attempts=$max_attempts
+    
+    while [ $remaining_attempts -gt 0 ]; do
+        if eval "$command"; then
+            return 0
+        fi
+        remaining_attempts=$((remaining_attempts - 1))
+        if [ $remaining_attempts -gt 0 ]; then
+            log "warn" "retry_with_backoff" "Command failed, $remaining_attempts retries remaining. Waiting ${delay_seconds}s..."
+            sleep "$delay_seconds"
+            delay_seconds=$((delay_seconds * 2))
+        fi
+    done
+    log "error" "retry_with_backoff" "Command failed after $max_attempts attempts"
+    return 1
+}