fix: resolve all CI test failures (19 fixes across 6 files) (#519)

- canonical-session: fall back to JSON file recording when the loaded
  state-store module has no writer methods (factory vs instance)
- install-executor: skip node_modules and .git dirs in listFilesRecursive
  to prevent ETIMEDOUT copying thousands of .opencode dependency files
- ecc.js: increase maxBuffer to 10MB for spawned subcommands to prevent
  ENOBUFS on large install plan JSON output
- install-apply.test: update Cursor and Antigravity path assertions to
  match flattened rule layout and remapped dirs (workflows, skills)
- ecc.test: increase maxBuffer in test runner to handle large output
- orchestrate-codex-worker.sh: guard against unreadable task file before
  cat, write failure status and handoff artifacts on early exit

scripts/orchestrate-codex-worker.sh

@@ -31,6 +31,21 @@ EOF
 }
 
 mkdir -p "$(dirname "$handoff_file")" "$(dirname "$status_file")"
+
+if [[ ! -r "$task_file" ]]; then
+  write_status "failed" "- Error: task file is missing or unreadable (\`$task_file\`)"
+  {
+    echo "# Handoff"
+    echo
+    echo "- Failed: $(timestamp)"
+    echo "- Branch: \`$(git rev-parse --abbrev-ref HEAD)\`"
+    echo "- Worktree: \`$(pwd)\`"
+    echo
+    echo "Task file is missing or unreadable: \`$task_file\`"
+  } > "$handoff_file"
+  exit 1
+fi
+
 write_status "running" "- Task file: \`$task_file\`"
 
 prompt_file="$(mktemp)"