feat: login-free Stockbit intraday and quote provider

Read Stockbit's public symbol page (__NEXT_DATA__) with a plain ureq
request and an honest user agent: `stocks intraday` (today by the
minute, any provider), `--provider stockbit` quotes with the best
bid/offer only while the market is open, and MCP `get_intraday`.

- UPSTREAMBLOCKED error (exit 4) for a CDN 403; never retried
- requests paced 1 s apart across idx processes, 5 s snapshot cache
- global --provider flag (yahoo, msn, stockbit)
- roadmap: L1 ships from Stockbit; depth stays a login follow-on

crates/idx-core/src/api/msn/map.rs

@@ -71,6 +71,10 @@ pub(super) fn parse_quote(symbol: &str, quotes: &[MsnQuote]) -> Result<Quote, Id
         avg_volume: round_u64(quote.average_volume),
         as_of: crate::api::parse_as_of(quote.time_last_traded.as_deref()),
         behind_session: false,
+        bid: None,
+        offer: None,
+        market_status: None,
+        session_note: None,
     })
 }
 
@@ -720,6 +724,10 @@ pub(super) fn parse_screener_results(raw: &RawScreenerResponse) -> Result<Vec<Qu
                 avg_volume: round_u64(q.average_volume),
                 as_of: crate::api::parse_as_of(q.time_last_traded.as_deref()),
                 behind_session: false,
+                bid: None,
+                offer: None,
+                market_status: None,
+                session_note: None,
             })
         })
         .collect();