experiment: facilitator panel beside workspace (Exp 05)

- Replace stacked landing with responsive two-column layout
- Left panel (1/3 desktop): facilitator intro card with dismiss checkbox
- Right panel (2/3 desktop): Tell me what's happening textarea + Analyse
- Mobile/tablet stack vertically as before
- 'Don't show' uses sessionStorage; future: user profile settings
- Close Exp 04 (Partially confirmed) in evolution log
- Add Exp 05 entry + Facilitator Behaviour UX section

docs/design-evolution-log.md

@@ -255,6 +255,47 @@ Questions
 Status:
 Experimental.
 
+Result:
+Partially confirmed.
+
+Learning:
+
+The facilitator introduction reduced the intimidation of the first screen.
+
+Replacing the empty landing page with a guided introduction improved the emotional tone.
+
+However, stacking the introduction above the input still gives the introduction excessive visual prominence.
+
+Repeat users may not want to repeatedly read the same introduction.
+
+Orientation should remain available without dominating the workflow.
+
+Decision:
+
+Keep the introduction concept but change its spatial relationship to the workspace — move it from above to beside, making it optional rather than mandatory.
+
+Next question:
+Does a horizontal facilitator/workspace layout feel more natural?
+
+### Experiment 05 — Facilitator Panel and Adaptive Landing Workspace
+
+Hypothesis
+
+Placing the facilitator beside the working area will feel more like entering a facilitated workshop than stacking instructional content above the workspace.
+
+Allowing the user to dismiss the facilitator will reduce friction for returning users while preserving onboarding for new users.
+
+Questions
+
+- Does a horizontal facilitator/workspace layout feel more natural?
+- Does the user's eye move naturally from facilitator to workspace?
+- Does the workspace become the primary focus?
+- Does "Don't show again" feel preferable to automatically hiding the introduction?
+- Should the facilitator panel become an optional workspace companion rather than mandatory onboarding?
+
+Status:
+Experimental.
+
 No conclusions.
 
 ---
@@ -269,3 +310,11 @@ The following are active explorations rather than decisions.
 - What information belongs in shared understanding?
 - What should the Investigation Map eventually become?
 - How should wide thinking be reflected in the interface?
+
+## Backlog — Experiment 05 Persistence Note
+
+The "Don't show this introduction again" checkbox uses sessionStorage as a placeholder.
+
+This preference should eventually be handled through user preferences or settings rather than local component state.
+
+TODO: When user accounts are introduced, persist this preference to the user profile so it travels across devices and sessions.