Pin Node version in .nvmrc instead of hardcoding it in the hook

Add a .nvmrc set to lts/krypton (matching CI's setup-node) and have the
SessionStart hook run `nvm install`/`nvm use` without a version argument so
the pinned version is the single source of truth.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NvxEaPhyEq2HCZ6XFjEAde

Author: claude

.claude/hooks/session-start.sh

@@ -3,8 +3,8 @@
 # SessionStart hook: bootstraps the repo so a fresh Claude Code worker can build,
 # lint and test the Node.js tooling packages out of the box.
 #
-# It ensures Node.js 24 (required by "devEngines" in package.json), installs the
-# npm workspace dependencies and builds the TypeScript project references.
+# It ensures the Node.js version pinned in .nvmrc (which matches CI), installs
+# the npm workspace dependencies and builds the TypeScript project references.
 #
 # Native iOS/Android artifacts are intentionally NOT built here: they require the
 # Android NDK / Apple toolchains which are not present on a generic Linux worker.
@@ -19,9 +19,10 @@ fi
 
 cd "${CLAUDE_PROJECT_DIR:-$(git rev-parse --show-toplevel)}"
 
-# --- Ensure Node.js 24 via nvm -----------------------------------------------
-# package.json's devEngines pins Node ^24 (and npm ^11); npm refuses to install
-# with an older runtime. nvm ships on the remote workers, so use it to select 24.
+# --- Ensure the Node.js version from .nvmrc via nvm ---------------------------
+# .nvmrc pins the Node version (matching CI). package.json's devEngines requires
+# Node ^24 / npm ^11, and npm refuses to install with an older runtime. nvm ships
+# on the remote workers, so use it to install and select the pinned version.
 NVM_DIR="${NVM_DIR:-/opt/nvm}"
 if [ ! -s "$NVM_DIR/nvm.sh" ] && [ -s "$HOME/.nvm/nvm.sh" ]; then
   NVM_DIR="$HOME/.nvm"
@@ -33,14 +34,15 @@ if [ -s "$NVM_DIR/nvm.sh" ]; then
   set +u
   # shellcheck disable=SC1091
   . "$NVM_DIR/nvm.sh"
-  nvm install 24 >/dev/null
-  nvm use 24 >/dev/null
+  # No version argument: nvm reads .nvmrc from the current directory.
+  nvm install >/dev/null
+  nvm use >/dev/null
+  NODE_BIN="$(dirname "$(nvm which current)")"
   set -u
 
-  NODE_BIN="$(dirname "$(nvm which 24)")"
   export PATH="$NODE_BIN:$PATH"
 
-  # Persist the Node 24 toolchain on PATH for the rest of the session.
+  # Persist the resolved Node toolchain on PATH for the rest of the session.
   if [ -n "${CLAUDE_ENV_FILE:-}" ]; then
     echo "export PATH=\"$NODE_BIN:\$PATH\"" >> "$CLAUDE_ENV_FILE"
   fi

.nvmrc

@@ -0,0 +1 @@
+lts/krypton

AGENTS.md

@@ -25,15 +25,15 @@ See the [README.md](README.md#packages) for detailed descriptions of each packag
 
 ## Environment & Bootstrap
 
-- **Node.js 24 is required** — `package.json`'s `devEngines` pins Node `^24` (and npm `^11`), and npm refuses to install with an older runtime.
+- **Node.js 24 is required** — pinned in `.nvmrc` as `lts/krypton` (matching CI); `package.json`'s `devEngines` requires Node `^24` and npm `^11`, and npm refuses to install with an older runtime. With nvm: `nvm install && nvm use`.
 - Standard setup for the Node.js tooling packages:
 
   ```bash
   npm install      # Install workspace dependencies
   npm run build    # Incremental TypeScript build (tsc --build)
   ```
 
-- On Claude Code on the web, `.claude/hooks/session-start.sh` performs the above automatically (selecting Node 24 via nvm) at session start.
+- On Claude Code on the web, `.claude/hooks/session-start.sh` performs the above automatically (selecting the `.nvmrc` version via nvm) at session start.
 - **Native (iOS/Android) builds are not part of the default bootstrap.** `npm run bootstrap` and the native `bootstrap` scripts compile artifacts that require the Android NDK / Apple toolchains, which are absent on a generic Linux worker. Focus on the Node.js tooling packages; pass an explicit target (e.g. `npx ferric --apple`) only when the corresponding SDK is installed.
 
 ## Critical Build Dependencies

CLAUDE.md

@@ -12,9 +12,10 @@ duplicating content here:
 ## Claude Code on the web
 
 A `SessionStart` hook (`.claude/hooks/session-start.sh`) bootstraps remote
-workers automatically: it selects Node.js 24 via `nvm` (required by
-`package.json`'s `devEngines`), then runs `npm install` and `npm run build`, so a
-fresh session is ready to build, lint, and test the Node.js tooling packages.
+workers automatically: it selects the Node.js version pinned in `.nvmrc` via
+`nvm` (Node 24, as required by `package.json`'s `devEngines`), then runs
+`npm install` and `npm run build`, so a fresh session is ready to build, lint,
+and test the Node.js tooling packages.
 
 See the "Environment & Bootstrap" section of `AGENTS.md` for the manual steps and
 for why native iOS/Android builds are not part of the default bootstrap.