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/tests/mcp.rs

@@ -9,12 +9,14 @@ use idx_core::config::CoreConfig;
 use idx_core::investor::{ImportSource, Investor};
 use serde_json::{Value, json};
 
-const TOOLS: [&str; 18] = [
+const TOOLS: [&str; 20] = [
     "analyze_bandar",
     "analyze_stock",
     "compare_stocks",
     "get_broker_summary",
     "get_company",
+    "get_corporate_actions",
+    "get_corporate_calendar",
     "get_foreign_flow",
     "get_intraday",
     "get_investor_holdings",
@@ -502,6 +504,53 @@ fn the_order_book_needs_a_session_and_status_never_shows_tokens() {
     }
 }
 
+#[test]
+fn corporate_actions_need_a_session_and_keep_kinds_apart() {
+    let mut client = Client::start(&[], false);
+    let (is_error, body) = client.call("get_corporate_actions", json!({"symbol": "BBCA"}));
+    assert!(is_error, "{body}");
+    assert_eq!(body["code"], "AUTHERROR");
+
+    let mut client = Client::start_with_env(
+        &[],
+        false,
+        &[TEST_SESSION, ("IDX_MOCK_TODAY", "2026-11-03")],
+    );
+    let actions = client.ok(
+        "get_corporate_actions",
+        json!({"symbol": "BBCA", "kinds": ["dividend", "split"]}),
+    );
+    assert_fetched(&actions);
+    assert_eq!(actions["source"], "stockbit");
+    let rows = actions["data"].as_array().unwrap();
+    assert_eq!(rows.len(), 40, "37 dividends and 3 splits");
+    assert_eq!(rows[0]["kind"], "dividend");
+    assert_eq!(rows[0]["date"], "2026-08-28");
+    assert_eq!(rows[0]["cash_per_share"], 25.0);
+    assert!(rows[0].get("ratio").is_none(), "absent fields are omitted");
+    let split = rows.iter().find(|r| r["kind"] == "split").unwrap();
+    assert_eq!(split["ratio"], json!({"old": 1, "new": 5}));
+
+    let calendar = client.ok(
+        "get_corporate_calendar",
+        json!({"to": "2026-11-12", "kinds": ["rights", "dividend"]}),
+    );
+    let rows = calendar["data"].as_array().unwrap();
+    assert_eq!(rows[0]["symbol"], "MGLV.JK");
+    assert_eq!(rows[0]["price"], 8880);
+    assert!(
+        rows.windows(2)
+            .all(|w| w[0]["date"].as_str() <= w[1]["date"].as_str())
+    );
+
+    let (is_error, body) = client.call(
+        "get_corporate_actions",
+        json!({"symbol": "BBCA", "kinds": ["rups"]}),
+    );
+    assert!(is_error, "{body}");
+    assert_eq!(body["code"], "INVALIDINPUT");
+}
+
 #[test]
 fn errors_carry_cli_codes() {
     let mut client = Client::start(&[], false);