feat: open-source release — AI-driven autonomous optimization with live visibility

Major upgrade making the AI loop visible and the project ready for public release.

UI / UX
- Live AI Thinking Feed: streams reasoning, decisions, and outcomes per iteration
- Parameter Changes panel: prev → new + reason for every AI-driven edit
- Validation Activity panel: out-of-sample + sensitivity runs with live metrics
- Early Termination banner: surfaces why optimization stopped (targets met, no profit, budget, stuck, user stop)
- 3-phase tracker renamed Exploration / Iteration / Validation with live N/total
- Best Result modal exposes Evolution Path showing how the AI arrived at the winner
- Run-detail modal accessible from every recent run row
- Setup form validation (dates, walk-forward order, params selection, AI targets)
- Pause button removed; misleading sidebar nav consolidated to Dashboard / New Run / Reports / Source

Backend
- AIGuidedLoop streams ai_thinking, param_changes, ai_targets_met, ai_stuck
- Pipeline emits validation_start / validation_run_start / validation_run_complete / validation_done
- Pipeline emits early_termination on every early-stop path
- /api/best_result returns best run + full evolution chain
- /api/run/<id> + /api/runs sorted by ts
- AIReasoner falls back to ANTHROPIC_API_KEY env var when config is a placeholder
- Demo mode (APEX_DEMO_MODE=1) generates deterministic synthetic backtests so judges can run end-to-end without MT5

Open-source readiness
- README.md with pitch, demo flow, architecture diagram, quickstart, event reference
- LICENSE (MIT)
- config.example.yaml template (config.yaml now git-ignored)
- requirements.txt: added anthropic / requests / psutil / beautifulsoup4, capped majors
- .gitignore: secrets, *.set, scratch screenshots, ea_registry.yaml
- demo/run_demo.py: one-command offline demo runner
- 10 polished screenshots for README + judge review

.gitignore

@@ -24,9 +24,33 @@ Reports/
 # Keep the optimizer database (optional — remove this line to commit it)
 optimizer.db
 
-# ── Sensitive Config (DO NOT COMMIT BROKER CREDENTIALS) ──────────────────────
-# config.yaml contains MT5 paths — safe to commit but exclude if it had passwords
-# config.secret.yaml
+# ── Sensitive Config (DO NOT COMMIT — contains API keys) ────────────────────
+# Users copy config.example.yaml → config.yaml and fill in their key locally.
+config.yaml
+.env
+.env.local
+*.secret.yaml
+*.secret.yml
+config.secret.yaml
+
+# ── EA Registry (machine-specific paths) ─────────────────────────────────────
+ea_registry.yaml
+
+# ── Generated set files ──────────────────────────────────────────────────────
+*.set
+!**/templates/*.set
+
+# ── Screenshots scratch (Playwright debug + health-test artifacts) ──────────
+screenshots/health_*.png
+screenshots/health_*.json
+screenshots/debug*.png
+screenshots/playwright_*.png
+screenshots/*.py
+screenshots/crop_*.png
+
+# ── Claude session artifacts ─────────────────────────────────────────────────
+Claude_Code_session*
+.claude/sessions/
 
 # ── Logs ──────────────────────────────────────────────────────────────────────
 *.log