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/ai/future-ai.md

@@ -0,0 +1,49 @@
+# Future AI Features
+
+Possible future features:
+
+---
+
+## AI Career Assistant
+
+A contextual assistant aware of:
+
+- Career history.
+- Goals.
+- Applications.
+
+---
+
+## Interview Coach
+
+Generate:
+
+- Questions.
+- Answers.
+- Feedback.
+
+---
+
+## Career Recommendations
+
+Suggest:
+
+- Skills.
+- Roles.
+- Learning paths.
+
+---
+
+## Automatic Application Assistant
+
+Potential:
+
+- Find relevant jobs.
+- Prepare documents.
+- Track progress.
+
+---
+
+# Priority
+
+Only build after core workflows are excellent.