When active-profile.json does not exist (fresh install or first boot after
update), seed it from the best available signal so the Desktop launches
into the user's primary profile instead of always defaulting to "default".
Priority ladder:
1. Legacy ~/.hermes/active_profile (explicit CLI choice via hermes profile use)
2. Running gateway (gateway.pid with verified liveness + hermes identity check
via /proc/cmdline or ps -o args= to avoid PID recycling false positives)
3. state.db heuristics — hybrid recency×size score picks the primary workspace
(e.g. a 409MB coder DB beats a 28MB default DB even if touched at similar times)
The stored JSON includes _migrated:true for priority 3 (heuristic guess) so
the renderer can optionally surface a one-time notification. Priority 1 and 2
are higher-confidence signals and skip the flag.
The migration is a no-op once active-profile.json exists, and only writes
when a non-default profile is confidently identified — preserving the legacy
fallback-to-default behavior for single-profile users.
Fixes#64160 (active-profile half).
4980a5ceae