[Watchlists] Sector sweep ranked summary table — HTML + Markdown output for batch runs

[DogInfantry]

Part of epic: #31
Depends on: #39 (--sector CLI flag must exist first)

What

When --sector is used, generate a ranked summary table across all tickers in the sweep in addition to individual stock notes. Output in both HTML and Markdown formats. This is the key demo artifact: a single file that shows the engine operating at institutional scale.

Output format

Technology Sector Sweep — 2026-04-16
┌────────┬─────────┬─────────┬─────────┬──────────┬──────────────┐
│ Rank   │ Ticker  │ Rating  │ TP ($)  │ Score    │ Key Driver   │
├────────┼─────────┼─────────┼─────────┼──────────┼──────────────┤
│ 1      │ NVDA    │ BUY     │ 950     │ 92/100   │ AI capex     │
│ 2      │ MSFT    │ BUY     │ 520     │ 88/100   │ Cloud growth │
│ 3      │ AAPL    │ HOLD    │ 210     │ 74/100   │ Services mix │
│ ...    │ ...     │ ...     │ ...     │ ...      │ ...          │
└────────┴─────────┴─────────┴─────────┴──────────┴──────────────┘

Implementation

def generate_sector_sweep_table(results: list[dict], sector: str) -> dict:
    """
    results: list of per-ticker pipeline output dicts, sorted by score desc
    Returns: {'html': str, 'markdown': str}
    """
    sorted_results = sorted(results, key=lambda x: x['score'], reverse=True)
    # build HTML table with color-coded rating cells
    # build Markdown table
    ...

Output files

• outputs/sector_{sector}_sweep_{date}.html
• outputs/sector_{sector}_sweep_{date}.md
• outputs/demo/sector_technology_sweep.html (committed demo)

Acceptance Criteria

• Sweep table generated automatically when --sector flag used
• Table sorted by screener score descending
• Rating cells colour-coded (BUY=green, HOLD=grey, SELL=red) in HTML
• Both HTML and Markdown outputs saved to outputs/
• Demo sweep committed to /outputs/demo/sector_technology_sweep.html
• Table renders correctly on GitHub (Markdown version)