docs: reorganize tree, restore architecture + research from archive, add Phase 0 reports

Active docs/ was stub scaffolding while the real docs sat in docs/_archive/.
Restore and correct them, and record the Phase 0 work.

- docs/architecture/current.md: verified system map (from archived SYSTEM_OVERVIEW,
  9 corrections against code).
- docs/research/competitors.md: sourced competitor analysis (from archived
  PRODUCT_RESEARCH, feature matrix corrected).
- docs/decisions/ADR-002-job-application-model.md: the Job/JobApplication split.
- docs/application-discovery-report.md, docs/implementation-roadmap.md,
  docs/phase-0-foundation-report.md, docs/career-workspace-branch-assessment.md.
- Remove 10 zero-byte placeholder files that advertised content that never existed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/ux/design-system.md

@@ -0,0 +1,74 @@
+# Design System
+
+## Design Direction
+
+Jobjakt should feel:
+
+- Modern.
+- Professional.
+- Premium.
+- Simple.
+- Intelligent.
+
+---
+
+# Inspirations
+
+Notion:
+
+- Organisation.
+- Content editing.
+
+Linear:
+
+- Professional software.
+
+FlowCV:
+
+- CV building experience.
+
+---
+
+# Colours
+
+Support:
+
+- Light mode.
+- Dark mode.
+
+Use:
+
+- Neutral backgrounds.
+- Clear accent colour.
+- Strong contrast.
+
+---
+
+# Components
+
+Maintain consistency:
+
+- Buttons.
+- Forms.
+- Cards.
+- Dialogs.
+- Tables.
+- Navigation.
+
+---
+
+# Typography
+
+Prioritise:
+
+- Readability.
+- Clear hierarchy.
+- Professional appearance.
+
+---
+
+# UX Rule
+
+Every screen should have:
+
+One obvious primary action.