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/architecture/overview.md

@@ -0,0 +1,93 @@
+# Application Architecture Overview
+
+## Purpose
+
+Define the target architecture direction for Jobjakt.
+
+This document does not require an immediate rewrite.
+
+The goal is incremental improvement while keeping the application functional.
+
+---
+
+# Product Architecture
+
+The application consists of:
+
+## Core Platform
+
+Job Tracking
+
+↓
+
+Applications
+
+↓
+
+Communication
+
+↓
+
+Follow-ups
+
+
+---
+
+## Supporting Platform
+
+Career Workspace
+
+↓
+
+Master Career Profile
+
+↓
+
+CV Builder
+
+↓
+
+Documents
+
+
+---
+
+## Intelligence Layer
+
+AI Services
+
+↓
+
+Recommendations
+
+↓
+
+Generation
+
+---
+
+# Architecture Goals
+
+The system should be:
+
+- Maintainable.
+- Testable.
+- Extensible.
+- Secure.
+- SaaS-ready.
+
+---
+
+# Evolution Strategy
+
+Prefer:
+
+- Refactoring.
+- Extraction.
+- Clear boundaries.
+- Incremental migrations.
+
+Avoid:
+
+- Large rewrites.
+- Replacing working systems unnecessarily.