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-mcp/src/params.rs

@@ -29,6 +29,15 @@ pub struct HistoryParams {
     pub interval: Option<String>,
 }
 
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct IntradayParams {
+    /// IDX ticker, e.g. "BBCA"; indices as "^JKSE" or "IHSG".
+    pub symbol: String,
+    /// Only the latest N minutes (default: the whole session, at most 400).
+    #[serde(default)]
+    pub tail: Option<usize>,
+}
+
 #[derive(Debug, Deserialize, JsonSchema)]
 pub struct ScreenParams {
     /// Screen to run (default "top-performers").