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/ecc.js

@@ -150,6 +150,7 @@ function runCommand(commandName, args) {
       cwd: process.cwd(),
       env: process.env,
       encoding: 'utf8',
+      maxBuffer: 10 * 1024 * 1024,
     }
   );