docs: Gemini code review of upstream PRs dlorenc#334 and dlorenc#336

Review findings for session ID fix (PR dlorenc#334) and error messages +
process detection (PR dlorenc#336) from dlorenc/multiclaude.

Both LGTM. One actionable finding: PR dlorenc#336 should handle EPERM
from signal(0) to avoid starting duplicate instances.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: whitmo

docs/reviews/upstream-pr-334-336-review.md

@@ -0,0 +1,58 @@
+# Gemini Code Review: Upstream PRs #334 and #336
+
+Reviewed via `gh pr diff <N> --repo dlorenc/multiclaude | gemini`
+
+## PR #334 — Session ID Fix (`fix(cli): generate new session ID when no history`)
+
+### Summary
+When `multiclaude claude` is run and no session history exists, generates a fresh UUID instead of reusing the old session ID. Fixes "Session ID is already in use" error after abnormal exits.
+
+### Verdict: LGTM
+
+| Area | Assessment |
+|------|-----------|
+| Correctness | Sound — new UUID on `!hasHistory`, reuse on `hasHistory` |
+| Error handling | `UpdateAgent` failure is non-fatal (warning + continue) — appropriate |
+| State consistency | `agent.SessionID` updated before persist — safe |
+| New dependency | `github.com/google/uuid` — standard, no concern |
+
+### Notes
+- Local variable `sessionID` introduced for clarity — slightly redundant with `agent.SessionID` but functionally correct
+- Risk: **Low** — isolated change, no new failure modes
+
+---
+
+## PR #336 — Error Messages + Process Detection
+
+### Summary
+1. Lowercases error strings to satisfy `staticcheck ST1005`
+2. Adds pre-restart process detection via `signal(0)` on agent PID and tmux pane PID
+
+### Verdict: LGTM with one suggestion
+
+| Area | Assessment |
+|------|-----------|
+| signal(0) usage | Correct on Unix |
+| Zombie handling | Covered — signal(0) returns error for zombies |
+| Race conditions | Minimal window — acceptable for CLI |
+| GetPanePID | Confirmed exists in `pkg/tmux/client.go` |
+| Error format | Multi-line with `\n` — unconventional Go but good CLI UX |
+
+### Actionable: EPERM handling (medium priority)
+
+If `signal(0)` returns `EPERM`, process is running but owned by different user. Current code treats this as "not running" and proceeds, potentially starting a duplicate.
+
+```go
+// Current
+if err == nil { return fmt.Errorf("already running...") }
+
+// Suggested
+if err == nil || errors.Is(err, syscall.EPERM) { return fmt.Errorf("already running...") }
+```
+
+Unlikely in normal usage (same user/machine) but is a correctness gap.
+
+### Minor notes (non-blocking)
+- `GetPanePID` errors silently swallowed — logging would help debugging
+- `repo` variable only needed for tmux check — slight scope expansion
+- Risk: **Low-Medium** — new code paths but failures handled gracefully