[BUG] Buddy persists across account switches — deterministic hash not re-evaluated on account swap

Description

When switching Claude Code accounts, the previous account's buddy persists instead of re-generating for the new account. On an account that has never drawn a buddy, a buddy still appears and speaks — carrying over from the previous session's account.

Steps to Reproduce

1. Log in as Account A — buddy is drawn and active
2. Switch to Account B (which has never drawn a buddy)
3. Run /buddy

Expected Behavior

• Account B should have no buddy (never drawn), or generate a new one based on Account B's accountUuid + salt → hash
• Buddy state should be account-scoped, not local-machine-scoped

Actual Behavior

• Account A's buddy persists on Account B
• The buddy speaks even though Account B never drew one
• Session continuity also seems to carry over (buddy behaves as if it "remembers" the previous session)

Root Cause (suspected)

~/.buddy-companion/state.json is not invalidated on account switch. The deterministic hash (accountUuid + salt → hash → species/rarity) is only evaluated at initial draw time, not re-evaluated when the active account changes.

As the buddy itself put it: "Deterministic hash ignoring account swap."

Related

• #42430 — buddy name/description stale after email change (similar identity mismatch)
• #42894 — buddy changed unexpectedly after update (salt/identity mismatch between versions)

Environment

• macOS
• Claude Code CLI