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/career/master-profile.md

@@ -0,0 +1,52 @@
+# Master CV
+
+## Purpose
+
+The Master CV represents the user's complete professional history.
+
+It is not necessarily the CV sent to employers.
+
+---
+
+# Relationship
+
+Career Profile
+
+↓
+
+Master CV
+
+↓
+
+Tailored CV
+
+---
+
+# Behaviour
+
+The Master CV contains:
+
+- All experience.
+- All skills.
+- All projects.
+- All achievements.
+
+A user may have more information here than appears in a final CV.
+
+---
+
+# Example
+
+Master CV:
+
+10 years experience.
+
+Generated CV:
+
+Only relevant 5 years shown.
+
+---
+
+# Rules
+
+Never overwrite master CV when creating tailored CVs.