feat(batch): add --model flag to batch-runner.sh (#504)

Forwards to claude -p --model, allowing cheaper-model batches without changing default behavior.

Author: joyson-fernandes

batch/batch-runner.sh

@@ -33,6 +33,7 @@ RETRY_FAILED=false
 START_FROM=0
 MAX_RETRIES=2
 MIN_SCORE=0
+MODEL=""  # empty = let claude -p use the Claude Max default
 
 usage() {
   cat <<'USAGE'
@@ -48,6 +49,9 @@ Options:
   --start-from N       Start from offer ID N (skip earlier IDs)
   --max-retries N      Max retry attempts per offer (default: 2)
   --min-score N        Skip PDF/tracker for offers scoring below N (default: 0 = off)
+  --model NAME         Claude model passed to `claude -p --model` (default:
+                       unset = Claude Max default). Use a cheaper model for
+                       large batches, e.g. `--model claude-sonnet-4-6`.
   -h, --help           Show this help
 
 Files:
@@ -81,6 +85,7 @@ while [[ $# -gt 0 ]]; do
     --start-from) START_FROM="$2"; shift 2 ;;
     --max-retries) MAX_RETRIES="$2"; shift 2 ;;
     --min-score) MIN_SCORE="$2"; shift 2 ;;
+    --model) MODEL="$2"; shift 2 ;;
     -h|--help) usage; exit 0 ;;
     *) echo "Unknown option: $1"; usage; exit 1 ;;
   esac
@@ -355,13 +360,17 @@ process_offer() {
     -e "s|{{ID}}|${esc_id}|g" \
     "$PROMPT_FILE" > "$resolved_prompt"
 
-  # Launch claude -p worker (uses default model from Claude Max subscription)
+  # Launch claude -p worker.
+  # Model defaults to the Claude Max subscription default unless --model was
+  # passed. Building the command in an array keeps quoting safe regardless.
+  local -a claude_args=(-p --dangerously-skip-permissions)
+  if [[ -n "$MODEL" ]]; then
+    claude_args+=(--model "$MODEL")
+  fi
+  claude_args+=(--append-system-prompt-file "$resolved_prompt" "$prompt")
+
   local exit_code=0
-  claude -p \
-    --dangerously-skip-permissions \
-    --append-system-prompt-file "$resolved_prompt" \
-    "$prompt" \
-    > "$log_file" 2>&1 || exit_code=$?
+  claude "${claude_args[@]}" > "$log_file" 2>&1 || exit_code=$?
 
   # Cleanup resolved prompt
   rm -f "$resolved_prompt"