## Problem
The `/running` endpoint in `listRunningProcessesHandler` reads
`process.state` directly without holding `stateMutex`. Meanwhile,
`swapState()` writes to `process.state` while holding the write lock.
This is a data race flagged by the Go race detector.
Also fixes a minor typo: "processes was in state" → "process was in
state".
## Fix
- `proxymanager.go`: Replace `process.state` with
`process.CurrentState()` which acquires `stateMutex.RLock()` before
reading.
- `process.go`: Fix typo in error message.
## Verification
- `gofmt -l` — clean
- `go test -run "TestProcessGroup_|TestProxyManager_" ./proxy/` — all
pass
- `go test ./proxy/config/... ./proxy/cache/...
./proxy/configwatcher/...` — all pass
