MSN Finance/Charts does not serve OHLCV data for XIDX stocks (returns 404).
Following the FP principle of not exposing capabilities a provider cannot fulfil:
- Remove impl HistoryProvider for MsnProvider entirely
- Remove fetch_charts from MsnClient
- Remove parse_chart_history, resample_history, trim_history_to_period from map.rs
- Remove MsnChart, ChartSeries, RawChart from raw_types.rs
- Remove parse_history_from_str, parse_close_only_history from parse.rs
- Decouple HistoryProvider from MarketDataProvider trait bound
- Add history_provider() factory: returns None for MSN, Some(Yahoo) for Yahoo
- CLI gates History/Technical on history_provider(), fails fast for MSN
- MSN mock returns Err(Unsupported); tests verify the behaviour explicitly
- financials: fix incomeStatement serde rename (was incomeStatements, API sends singular)
- financials: flatten nested sub-objects (income/revenue/expense/cash) in parse_statement_section
- insights: rewrite RawInsight to match actual API shape ({insights:[{insightName,insightStatement,category}]})
- insights: group insight items into highlights (non-risk) and risks by category
- screener: build Quote directly in parse_screener_results, skip stocks with no price
- profile: use short_name fallback when long_name is null, hide empty fields
- history: map Finance/Charts 404 to Unsupported with clear IDX-specific message
- tests: update MSN history/technical tests to use mock provider
