fix: v0.3.1 local surface migration, bug fixes, and scan visibility

[Codex-Crusader]

• Migrate pulseengine/local/ from forward shims to full production implementations
• Convert dashboard/, app/scan.py to reverse shims for backward compat
• Fix dry-run writing per-asset snapshots (save=not dry_run)
• Fix manual scan not auto-refreshing UI after completion (_scan_rerun_done)
• Fix scan progress invisible in terminal (configure pulseengine logger at INFO, verbose=True)
• Update test patch target to pulseengine.local.scan._save_summary
• Update CHANGELOG, ROADMAP, CONTRIBUTING, variable_list, code_flow docs

[Codex-Crusader]

Summary

• Full production code migrated into `pulseengine/local/` (dashboard, components, styles, data, scan); old paths become reverse shims
• Bug: dry-run mode was writing per-asset snapshots - fixed (`save=not dry_run`)
• Bug: manual scan never auto-refreshed the UI - fixed (`_scan_rerun_done = False` on scan start)
• Bug: scan progress was invisible in terminal - fixed (pulseengine logger configured at INFO with StreamHandler)
• Docs updated: CHANGELOG, ROADMAP version badge, CONTRIBUTING test count, variable_list paths, code_flow paths

Test plan

• `pytest` - 54 passing
• `streamlit run pulseengine/local/dashboard.py` - scan progress visible in terminal
• `python -m pulseengine.local.scan --dry-run` - no .json.gz files written
• `streamlit run dashboard/main.py` - backward-compat shim still works