fix(cli)(sphere-sdk#247): refuse CLI when a sphere daemon holds the OrbitDB lock

[vrogojin]

Summary

Short-term mitigation for the §C.4 "Database is not open" failure observed in `manual-test-full-recovery.sh` (unicity-sphere/sphere-sdk#247).

The daemon parks the event loop forever with OrbitDB / Helia open; LevelDB takes a POSIX advisory file lock (`fcntl(F_SETLK)`) on `/orbitdb//_index/LOCK` and on `/datastore/LOCK`. A sibling CLI in the same dataDir hits `LEVEL_LOCKED` → `Database is not open`, and the bounded retry from sphere-sdk PR #246 can never succeed (the contention isn't transient).

This gate detects the live-daemon case in `getSphere()` and exits with `EX_TEMPFAIL` (75), telling the operator to `sphere daemon stop` first. Skipped when our own PID owns the PID file (`daemon start` calling back into `getSphere` is the legitimate owner). Bypassed for `daemon stop`/`status` (which don't go through `getSphere`).

The proper long-term fix is a daemon-as-broker IPC surface (sphere-sdk#247 follow-up: Unix domain socket at `/.sphere-cli/daemon.sock` + RemoteOrbitDbAdapter mirroring the OrbitDbAdapter interface, so CLI commands talk to the running daemon instead of opening OrbitDB directly).

Changes

• `src/legacy/daemon.ts`: export `readPidFile` and `isDaemonProcessAlive` (previously file-private helpers) so the CLI's getSphere can reuse them.
• `src/legacy/legacy-cli.ts`: add `checkNoLiveDaemonOrExit()` and call it at the start of `getSphere()`. Print a clear message + EX_TEMPFAIL on contention.

Test plan

• `npm run build` — clean.
• Manual: running `sphere balance` while a daemon is alive in the same CWD exits cleanly with the operator hint, instead of hanging on the retry budget.
• Manual: `sphere daemon start` itself still works (it owns the PID file; the gate's self-skip kicks in).
• Manual: `sphere daemon stop` / `status` still work (they don't go through getSphere).
• sphere-sdk's `manual-test-full-recovery.sh` (with the companion stop+start §C.4 change) passes §A–§C.3 cleanly; previously hit "Database is not open".

Companion

Stacks with sphere-sdk `fix/issue-247-residuals` (which also updates the manual-test script to stop+start the daemons around §C.4).