[v0.3] Create pulseengine/local/ surface with full-feature Streamlit dashboard

[Codex-Crusader]

Parent Issue

Part of #31 — v0.3 Repo Restructure

Depends on #32 — core/ must be in place before this work begins.

Context

The current dashboard/ directory contains the full Streamlit dashboard (main.py, components.py, styles.py, data.py), and app/scan.py handles the full-market batch scan. Under the v0.3 restructure these all move into pulseengine/local/.

local/ is the full-power surface — it can be heavy. FinBERT, backtesting, snapshot storage, large file I/O — all fine here. No size or compute apologies.

Files to Move / Create

Current Path	Target Path
dashboard/main.py	pulseengine/local/dashboard.py
dashboard/components.py	pulseengine/local/components.py
dashboard/styles.py	pulseengine/local/styles.py
dashboard/data.py	pulseengine/local/data.py
app/scan.py	pulseengine/local/scan.py

All imports from core/ are used via pulseengine.core.*.

Feature Completeness

local/ must expose every feature listed as "Yes" in the Local App column of the ROADMAP feature table:

• All 24 current tracked assets
• Signal score + explanation
• Price chart
• News sentiment feed
• Market heatmap
• Category overview
• Arbitrary ticker lookup (tracked in the separate arbitrary ticker issue)
• Backtesting
• Historical snapshots
• Export to CSV / PDF (tracked in v0.5 — placeholder OK for now)
• Offline mode (tracked in v0.5 — placeholder OK for now)

Acceptance Criteria

• pulseengine/local/dashboard.py launches correctly with streamlit run pulseengine/local/dashboard.py
• Dashboard renders all existing asset categories and signal views without regression
• pulseengine/local/scan.py runs full 24-asset scan and writes snapshots correctly
• pulseengine/local/__init__.py present
• No direct imports from dashboard/ old path remain
• All existing tests pass

Notes

Locked features (arbitrary ticker, FinBERT, export, offline) should display a "coming soon" or greyed-out placeholder in the UI where the roadmap calls for them — do not silently omit them.