Issue 4.27 multi-instance plugin-runtime-deps hash mismatch

** https://github.com/openclaw/openclaw/issues/new

Title:

[BUG] 4.27 multi-instance: plugin-runtime-deps hash mismatch causes ENOENT on bundled channel dist files

Labels: bug

Body:

## 📌 Description

After upgrading to OpenClaw 4.27, running multiple Gateway instances (5x via PM2 on Windows) causes `plugin-runtime-deps` directory hash mismatch. Each instance generates a different hash (e.g., `5f4e2e59ed9a` vs `456555aaef5c`), but some instances fail to find the correct dist files.

## 🐛 Symptoms

[channels] failed to load bundled channel discord: ENOENT: no such file or directory, open 'C:\Users\Administrator.openclaw\plugin-runtime-deps\openclaw-2026.4.27-456555aaef5c\dist\channel-reply-pipeline-DIVeGRyD.js'
[channels] failed to load bundled channel feishu: ENOENT: ... openclaw-2026.4.27-456555aaef5c\dist\channel-options-UH47ik5d.js'
[channels] failed to load bundled channel googlechat: ENOENT: ... openclaw-2026.4.27-456555aaef5c\dist\browser-lifecycle-cleanup-C2Oo2ffe.js'
[channels] failed to load bundled channel imessage: ENOENT: ... openclaw-2026.4.27-456555aaef5c\dist\channel-BNoltDfW.js'
[channels] failed to load bundled channel line: ENOENT: ... openclaw-2026.4.27-456555aaef5c\dist\channel-runtime-contexts-BUb7qx3p.js'
[channels] failed to load bundled channel irc: ENOENT: ... openclaw-2026.4.27-456555aaef5c\dist\cache-controls-DyMccij0.js'
... (all channels affected on affected instances)

## 🖥️ Environment

- OS: Windows Server (PM2 multi-instance: openclaw-gw1 ~ openclaw-gw5)
- OpenClaw: 2026.4.27
- Node: v22.x
- PM2: running 5 gateway instances

## 📊 Additional Metrics

eventLoopDelayMaxMs=11827.9
eventLoopUtilization=0.637
cpuCoreRatio=0.676
active=0 waiting=0 queued=0

## 🔍 Suspected Root Cause

The `plugin-runtime-deps` instance hash is derived from some instance-specific identifier that differs across PM2 workers. When one instance installs/updates the runtime deps into a hash-based directory, other instances may either:

1. Create a different hash directory and fail to find shared dist files, OR
2. Race condition during the same hash directory population causes partial file writes

## 📝 Expected Behavior

All gateway instances on the same host should share a single `plugin-runtime-deps` directory per version, or each instance should have its own isolated deps directory that actually works.