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/jobs/communication-tracking.md

@@ -0,0 +1,49 @@
+# Communication Tracking
+
+## Purpose
+
+Store application history.
+
+---
+
+# Sources
+
+Manual:
+
+- Notes.
+- Calls.
+- Messages.
+
+Automatic:
+
+- Email integrations.
+
+---
+
+# Email Providers
+
+Supported:
+
+- Gmail.
+- Microsoft.
+- IMAP.
+
+---
+
+# Storage
+
+Communication should belong to:
+
+Application
+
+or
+
+Company
+
+depending on context.
+
+---
+
+# Privacy
+
+Users control connected accounts.