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/product/goals.md

@@ -0,0 +1,111 @@
+# Product Goals
+
+## Purpose
+
+Defines the outcomes Jobjakt should achieve.
+
+---
+
+# Primary Goals
+
+## Goal 1: Excellent Job Tracking
+
+Priority: Highest
+
+Users should have the best possible experience managing applications.
+
+Requirements:
+
+- Easy job creation.
+- Clear application stages.
+- Communication tracking.
+- Follow-up reminders.
+- Search and filtering.
+
+---
+
+## Goal 2: Build a Reliable Career Profile
+
+Users should maintain one source of truth.
+
+Includes:
+
+- Experience.
+- Skills.
+- Education.
+- Projects.
+- Certifications.
+
+---
+
+## Goal 3: Improve Application Quality
+
+Help users create stronger applications.
+
+Features:
+
+- CV generation.
+- AI improvements.
+- Cover letters.
+- Job matching.
+
+---
+
+## Goal 4: Reduce Application Effort
+
+The system should make repetitive tasks easier.
+
+Examples:
+
+- Import jobs.
+- Extract CV data.
+- Generate documents.
+- Reuse career information.
+
+---
+
+## Goal 5: Create SaaS Foundation
+
+Prepare for future commercialisation.
+
+Support:
+
+- Multiple users.
+- Billing.
+- Premium features.
+- Usage limits.
+
+Do not compromise current UX.
+
+---
+
+# Secondary Goals
+
+- Job discovery.
+- Public CVs.
+- Portfolio pages.
+- Interview preparation.
+- Career analytics.
+
+---
+
+# Success Metrics
+
+Potential metrics:
+
+## Engagement
+
+- Applications tracked.
+- Jobs added.
+- CVs generated.
+
+## Quality
+
+- Completed applications.
+- Follow-ups completed.
+- User feedback.
+
+## Retention
+
+- Returning users.
+- Active job searches.