chore(ms-ai-architect): scrub identifying references from fixtures + remove screenshots

Removes:
- All 6 PNG screenshots (playground/screenshots/) and the capture script
  (scripts/screenshots/capture-playground.py).
- "Screenshots" section from plugin README.
- "Screenshot-suite" section from plugin CLAUDE.md.
- Screenshots bullet from marketplace root README's ms-ai-architect listing.

Scrubs the 17 synthetic fixtures + CHANGELOG/CLAUDE/README of identifying
references: organization names, government-agency names, agency-specific
terminology, sector-specific use cases. Replaced with generic placeholder
data ("Acme AS" / "Demosystem") that exercises the same parser archetypes.

Plugin's domain-target wording (Datatilsynet, offentlig sektor, offentlig
myndighet, rettshåndhevelse, NS 5814, Utredningsinstruksen, EU AI Act
Annex III categories) is intact — those describe the plugin's intended
audience, not any specific entity.

This is a cleanup commit. Earlier git history still contains the prior
references; force-push or rebase is required if scrubbing the history is
desired. That decision is out of scope here — please run it separately
if needed.

Verified post-scrub:
- bash tests/validate-plugin.sh -> 215/215 PASS
- bash tests/run-e2e.sh --playground -> 240/240 PASS (170 + 70)

plugins/ms-ai-architect/playground/test-fixtures/ros.md

@@ -1,6 +1,6 @@
-# ROS-analyse — ANPR-trafikkanalyse
+# ROS-analyse — Demosystem
 
-System: ANPR-trafikkanalyse (Statens vegvesen)
+System: Demosystem (Acme AS)
 Metodikk: NS 5814 / ISO 31000 + AI-trusselbibliotek
 
 ## Risikomatrise (5×5)
@@ -14,7 +14,7 @@ Metodikk: NS 5814 / ISO 31000 + AI-trusselbibliotek
 | Klage-saksbehandling overbelastet ved skalering | 4 | 3 | 12 | medium |
 | Datatap pga manglende georedundans | 1 | 5 | 5 | low |
 | Misbruk av AI-forklaring som bevis | 3 | 4 | 12 | medium |
-| Kjedevirkning ved feil i kjøretøyregister | 2 | 5 | 10 | medium |
+| Kjedevirkning ved feil i objektregister | 2 | 5 | 10 | medium |
 
 ## Radar-akser (7 dimensjoner)