feat: corporate actions from the Stockbit session (stocks actions, stocks calendar)

`idx stocks actions SYM [--kind ...]`: one stock's cash and stock
dividends, bonus shares, rights, warrants, splits and reverse splits,
meetings, public exposes and tender offers (`--kind ipo` adds its IPO),
newest first. `idx stocks calendar [--from] [--to] [--kind ...]`: the
market's actions dated in the range (default today and 30 days ahead),
oldest first. MCP: get_corporate_actions, get_corporate_calendar.

Stockbit's `/corpaction/{type}` serves one kind per request; each type has
its own field prefix and list key, so entitlements are read by field
suffix. An action's `date` is the cum date for entitlements, else the
event's first day. Dividends keep their decimals. One request per kind,
cached 6 hours. AUTHERROR without a session.

Fixtures are the 2026-11-03 recordings (market-wide ones trimmed to
October-December). Goldens added; help-stocks and completions-bash gain
the two subcommands, MCP tools.json the two tools (regenerated with
UPDATE_GOLDEN=1). The MCP docs counted 17 tools without stockbit_login;
now 20.

Claude-Session: https://claude.ai/code/session_01RqPPVeVDrnLoP7NUZmLRxY

crates/idx-mcp/src/params.rs

@@ -4,6 +4,7 @@
 use idx_core::analysis::bandar::TIERS;
 use idx_core::api::types::{Interval, Period};
 use idx_core::broker::types::{BrokerBoard, BrokerInvestor};
+use idx_core::corporate::types::ActionKind;
 use idx_core::flow::types::FlowSource;
 use idx_core::market::{ScreenFilter, ScreenRegion};
 use schemars::{JsonSchema, Schema, SchemaGenerator, json_schema};
@@ -228,6 +229,41 @@ pub struct FlowParams {
     pub source: Option<String>,
 }
 
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct CorporateActionsParams {
+    /// IDX ticker, e.g. "BBCA".
+    pub symbol: String,
+    /// Kinds to list (default: every kind but "ipo"). Each kind is one request to Stockbit.
+    #[serde(default)]
+    #[schemars(schema_with = "action_kinds_schema")]
+    pub kinds: Option<Vec<String>>,
+}
+
+#[derive(Debug, Deserialize, JsonSchema)]
+pub struct CorporateCalendarParams {
+    /// First day, YYYY-MM-DD (default today).
+    #[serde(default)]
+    pub from: Option<String>,
+    /// Last day, YYYY-MM-DD (default 30 days after `from`; at most 366 days).
+    #[serde(default)]
+    pub to: Option<String>,
+    /// Kinds to list (default: every kind). Each kind is one request to Stockbit.
+    #[serde(default)]
+    #[schemars(schema_with = "action_kinds_schema")]
+    pub kinds: Option<Vec<String>>,
+}
+
+/// Parses `kinds`, or `default` when absent.
+pub fn action_kinds(
+    kinds: Option<Vec<String>>,
+    default: &[ActionKind],
+) -> Result<Vec<ActionKind>, idx_core::error::IdxError> {
+    match kinds {
+        None => Ok(default.to_vec()),
+        Some(kinds) => kinds.iter().map(|k| k.parse()).collect(),
+    }
+}
+
 #[derive(Debug, Deserialize, JsonSchema)]
 pub struct ShareholdersParams {
     /// IDX ticker, e.g. "BBCA".
@@ -305,6 +341,11 @@ fn flow_source_schema(_: &mut SchemaGenerator) -> Schema {
     string_enum(FlowSource::ALL.map(FlowSource::as_str).to_vec())
 }
 
+fn action_kinds_schema(_: &mut SchemaGenerator) -> Schema {
+    let kinds: Vec<&str> = ActionKind::ALL.iter().map(|k| k.as_str()).collect();
+    json_schema!({ "type": "array", "items": { "type": "string", "enum": kinds } })
+}
+
 fn login_method_schema(_: &mut SchemaGenerator) -> Schema {
     string_enum(LoginMethod::ALL.map(LoginMethod::as_str).to_vec())
 }