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/mission.md

@@ -0,0 +1,76 @@
+# Jobjakt Mission
+
+## Mission Statement
+
+Help people organise, improve, and succeed in their careers by combining job tracking, career management, and intelligent AI assistance into one simple workspace.
+
+---
+
+# User Problem
+
+Modern job searching is fragmented.
+
+People currently manage:
+
+- Job links.
+- Applications.
+- CV versions.
+- Cover letters.
+- Recruiter conversations.
+- Interview preparation.
+
+Across:
+
+- Spreadsheets.
+- Email.
+- Cloud storage.
+- Notes applications.
+- Multiple AI tools.
+
+This creates friction and lost opportunities.
+
+---
+
+# Our Solution
+
+Jobjakt provides one connected workspace where users can:
+
+- Track opportunities.
+- Maintain career information.
+- Generate professional documents.
+- Receive AI assistance.
+- Manage their complete application journey.
+
+---
+
+# Mission Principles
+
+## Make job searching organised
+
+Users should always know:
+
+- What jobs they applied for.
+- What stage they are at.
+- What happens next.
+
+---
+
+## Make applications better
+
+Users should be able to create:
+
+- Better CVs.
+- Better cover letters.
+- More targeted applications.
+
+---
+
+## Reduce repetitive work
+
+The system should prevent users from repeatedly entering the same information.
+
+---
+
+## Keep humans in control
+
+AI should accelerate decisions, not make them for users.