Rename ephemeral -> wisp terminology throughout Gas Town

- .beads-ephemeral/ -> .beads-wisp/
- Rename doctor checks: EphemeralCheck -> WispCheck
- Update all docs to use 'transient' for polecats, 'wisp' for molecules
- Preserve 'ephemeral' only as descriptive adjective for wisps
- Steam engine metaphor: wisps are steam vapors that dissipate

Part of Christmas launch wisp terminology unification.

prompts/roles/crew.md

@@ -4,7 +4,7 @@
 
 ## Your Role: CREW WORKER ({{ name }} in {{ rig }})
 
-You are a **crew worker** - the overseer's (human's) personal workspace within the {{ rig }} rig. Unlike polecats which are witness-managed and ephemeral, you are:
+You are a **crew worker** - the overseer's (human's) personal workspace within the {{ rig }} rig. Unlike polecats which are witness-managed and transient, you are:
 
 - **Persistent**: Your workspace is never auto-garbage-collected
 - **User-managed**: The overseer controls your lifecycle, not the Witness
@@ -157,7 +157,7 @@ Before ending your session:
 
 ## Tips
 
-- **You own your workspace**: Unlike polecats, you're not ephemeral. Keep it organized.
+- **You own your workspace**: Unlike polecats, you're not transient. Keep it organized.
 - **Handoff liberally**: When in doubt, write a handoff mail. Context is precious.
 - **Stay in sync**: Pull from upstream regularly to avoid merge conflicts.
 - **Ask for help**: No Witness means no automatic escalation. Reach out proactively.

prompts/roles/polecat.md

@@ -4,10 +4,10 @@
 
 ## Your Role: POLECAT ({{ name }} in {{ rig }})
 
-You are a **polecat** - an ephemeral worker agent in the Gas Town swarm. You are:
+You are a **polecat** - a transient worker agent in the Gas Town swarm. You are:
 
 - **Task-focused**: You work on one assigned issue at a time
-- **Ephemeral**: When your work is done, you may be decommissioned
+- **Transient**: When your work is done, you may be decommissioned
 - **Witness-managed**: The Witness monitors your progress and can nudge or reassign you
 - **Part of a swarm**: Other polecats may be working on related issues in parallel
 

prompts/roles/witness.md

@@ -260,8 +260,8 @@ Before killing ANY polecat session, verify:
 
 **If all checks pass:**
 1. Kill session: `tmux kill-session -t gt-{{ rig }}-<name>`
-2. Remove worktree: `git worktree remove polecats/<name>` (if ephemeral)
-3. Delete branch: `git branch -d polecat/<name>` (if ephemeral)
+2. Remove worktree: `git worktree remove polecats/<name>` (if transient)
+3. Delete branch: `git branch -d polecat/<name>` (if transient)
 
 ---
 
@@ -303,7 +303,7 @@ tmux capture-pane -t gt-{{ rig }}-<name> -p | tail -40
 # Session control
 tmux kill-session -t gt-{{ rig }}-<name>
 
-# Worktree cleanup (for ephemeral polecats)
+# Worktree cleanup (for transient polecats)
 git worktree remove polecats/<name>
 git branch -d polecat/<name>