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/accessibility.md

@@ -0,0 +1,47 @@
+# Accessibility Requirements
+
+## Goal
+
+Make Jobjakt usable by as many people as possible.
+
+---
+
+# Requirements
+
+Support:
+
+- Keyboard navigation.
+- Screen readers.
+- Proper labels.
+- Focus states.
+- Colour contrast.
+
+---
+
+# Forms
+
+Every field requires:
+
+- Label.
+- Validation message.
+- Helpful error.
+
+---
+
+# Documents
+
+CV previews should consider:
+
+- Text readability.
+- Contrast.
+- Print output.
+
+---
+
+# Testing
+
+Use:
+
+- Lighthouse.
+- Axe.
+- Manual testing.