fix(core): apply security/robustness fix round and sync fork

- security: redact provider API keys in /provider responses; timing-safe instance auth
- contract: converge v2.session.messages dual operationId; move message cursor + default limit into protocol/server; regenerate SDK
- runner: read SessionToolPermissions for subagent read-only defaults; bound repeated tool calls; title generation; accumulate step usage; settleWith tolerates StorageError
- cleanup: remove fake spawn_agent chain, subagent fork leftovers, dead code files; prune unused audio/sst-env; update merge-clean paths

Author: 3kaiu

AGENTS.md

@@ -1,5 +1,5 @@
 - To regenerate the legacy JavaScript SDK, run `./packages/sdk/js/script/build.ts`.
-- After changing the public Protocol or Server `HttpApi`, run `bun run generate` from `packages/client`. Do not edit `src/generated` or `src/generated-effect` directly.
+- After changing the public Protocol or Server `HttpApi`, regenerate the OpenAPI spec with `bun dev generate` from `packages/opencode` (the CLI `generate` command at `packages/opencode/src/cli/cmd/generate.ts`; the SDK build consumes it via `packages/sdk/js/script/build.ts`). Do not edit `src/generated` or `src/generated-effect` directly.
 - Keep runtime dependencies directed from Schema to Core and Protocol, then from Core and Protocol to Server. Client runtime code may depend on Schema and Protocol but never Core or Server; `sdk-next` composes Client, Core, and Server.
 - The default branch in this repo is `dev`.
 - Local `main` ref may not exist; use `dev` or `origin/dev` for diffs.

MERGE.md

@@ -0,0 +1,155 @@
+export * as BashArity from "./arity"
+
+const ARITY: Record<string, number> = {
+  cat: 1, // cat file.txt
+  cd: 1, // cd /path/to/dir
+  chmod: 1, // chmod 755 script.sh
+  chown: 1, // chown user:group file.txt
+  cp: 1, // cp source.txt dest.txt
+  echo: 1, // echo "hello world"
+  env: 1, // env
+  export: 1, // export PATH=/usr/bin
+  grep: 1, // grep pattern file.txt
+  kill: 1, // kill 1234
+  killall: 1, // killall process
+  ln: 1, // ln -s source target
+  ls: 1, // ls -la
+  mkdir: 1, // mkdir new-dir
+  mv: 1, // mv old.txt new.txt
+  ps: 1, // ps aux
+  pwd: 1, // pwd
+  rm: 1, // rm file.txt
+  rmdir: 1, // rmdir empty-dir
+  sleep: 1, // sleep 5
+  source: 1, // source ~/.bashrc
+  tail: 1, // tail -f log.txt
+  touch: 1, // touch file.txt
+  unset: 1, // unset VAR
+  which: 1, // which node
+  aws: 3, // aws s3 ls
+  az: 3, // az storage blob list
+  bazel: 2, // bazel build
+  brew: 2, // brew install node
+  bun: 2, // bun install
+  "bun run": 3, // bun run dev
+  "bun x": 3, // bun x vite
+  cargo: 2, // cargo build
+  "cargo add": 3, // cargo add tokio
+  "cargo run": 3, // cargo run main
+  cdk: 2, // cdk deploy
+  cf: 2, // cf push app
+  cmake: 2, // cmake build
+  composer: 2, // composer require laravel
+  consul: 2, // consul members
+  "consul kv": 3, // consul kv get config/app
+  crictl: 2, // crictl ps
+  deno: 2, // deno run server.ts
+  "deno task": 3, // deno task dev
+  doctl: 3, // doctl kubernetes cluster list
+  docker: 2, // docker run nginx
+  "docker builder": 3, // docker builder prune
+  "docker compose": 3, // docker compose up
+  "docker container": 3, // docker container ls
+  "docker image": 3, // docker image prune
+  "docker network": 3, // docker network inspect
+  "docker volume": 3, // docker volume ls
+  eksctl: 2, // eksctl get clusters
+  "eksctl create": 3, // eksctl create cluster
+  firebase: 2, // firebase deploy
+  flyctl: 2, // flyctl deploy
+  gcloud: 3, // gcloud compute instances list
+  gh: 3, // gh pr list
+  git: 2, // git checkout main
+  "git config": 3, // git config user.name
+  "git remote": 3, // git remote add origin
+  "git stash": 3, // git stash pop
+  go: 2, // go build
+  gradle: 2, // gradle build
+  helm: 2, // helm install mychart
+  heroku: 2, // heroku logs
+  hugo: 2, // hugo new site blog
+  ip: 2, // ip link show
+  "ip addr": 3, // ip addr show
+  "ip link": 3, // ip link set eth0 up
+  "ip netns": 3, // ip netns exec foo bash
+  "ip route": 3, // ip route add default via 1.1.1.1
+  kind: 2, // kind delete cluster
+  "kind create": 3, // kind create cluster
+  kubectl: 2, // kubectl get pods
+  "kubectl kustomize": 3, // kubectl kustomize overlays/dev
+  "kubectl rollout": 3, // kubectl rollout restart deploy/api
+  kustomize: 2, // kustomize build .
+  make: 2, // make build
+  mc: 2, // mc ls myminio
+  "mc admin": 3, // mc admin info myminio
+  minikube: 2, // minikube start
+  mongosh: 2, // mongosh test
+  mysql: 2, // mysql -u root
+  mvn: 2, // mvn compile
+  ng: 2, // ng generate component home
+  npm: 2, // npm install
+  "npm exec": 3, // npm exec vite
+  "npm init": 3, // npm init vue
+  "npm run": 3, // npm run dev
+  "npm view": 3, // npm view react version
+  nvm: 2, // nvm use 18
+  nx: 2, // nx build
+  openssl: 2, // openssl genrsa 2048
+  "openssl req": 3, // openssl req -new -key key.pem
+  "openssl x509": 3, // openssl x509 -in cert.pem
+  pip: 2, // pip install numpy
+  pipenv: 2, // pipenv install flask
+  pnpm: 2, // pnpm install
+  "pnpm dlx": 3, // pnpm dlx create-next-app
+  "pnpm exec": 3, // pnpm exec vite
+  "pnpm run": 3, // pnpm run dev
+  poetry: 2, // poetry add requests
+  podman: 2, // podman run alpine
+  "podman container": 3, // podman container ls
+  "podman image": 3, // podman image prune
+  psql: 2, // psql -d mydb
+  pulumi: 2, // pulumi up
+  "pulumi stack": 3, // pulumi stack output
+  pyenv: 2, // pyenv install 3.11
+  python: 2, // python -m venv env
+  rake: 2, // rake db:migrate
+  rbenv: 2, // rbenv install 3.2.0
+  "redis-cli": 2, // redis-cli ping
+  rustup: 2, // rustup update
+  serverless: 2, // serverless invoke
+  sfdx: 3, // sfdx force:org:list
+  skaffold: 2, // skaffold dev
+  sls: 2, // sls deploy
+  sst: 2, // sst deploy
+  swift: 2, // swift build
+  systemctl: 2, // systemctl restart nginx
+  terraform: 2, // terraform apply
+  "terraform workspace": 3, // terraform workspace select prod
+  tmux: 2, // tmux new -s dev
+  turbo: 2, // turbo run build
+  ufw: 2, // ufw allow 22
+  vault: 2, // vault login
+  "vault auth": 3, // vault auth list
+  "vault kv": 3, // vault kv get secret/api
+  vercel: 2, // vercel deploy
+  volta: 2, // volta install node
+  wp: 2, // wp plugin install
+  yarn: 2, // yarn add react
+  "yarn dlx": 3, // yarn dlx create-react-app
+  "yarn run": 3, // yarn run dev
+}
+
+/**
+ * Longest-matching-prefix command arity: how many tokens make up the
+ * human-understandable command. `git commit -m "x"` -> `git commit`,
+ * `npm run dev` -> `npm run dev`.
+ */
+export function prefix(tokens: readonly string[]): readonly string[] {
+  for (let len = tokens.length; len > 0; len--) {
+    const prefix = tokens.slice(0, len).join(" ")
+    const arity = ARITY[prefix]
+    if (arity !== undefined) return tokens.slice(0, arity)
+  }
+  if (tokens.length === 0) return []
+  return tokens.slice(0, 1)
+}