fix(ownership): correct changes, alias search, graph, and name lookups

From a full-repo Codex audit, each reproduced on the synced ownership DB:
- `changes` paired an investor's accounts across releases instead of
  comparing totals: KREN's KRESNA PRIMA INVEST went 9.44% -> 13.45% (a
  second 4.01% account) but was reported as decreased 944 -> 401 bps.
  Sum a holder's accounts per ticker, and read one release per date (the
  latest imported, as other queries do), so a corrected file supersedes
  the original instead of mixing with it.
- `changes` / get_ownership_changes accepted any dates: `from: ""`
  reported all 7,154 holders as new, unknown dates returned no changes.
  Dates must be YYYY-MM-DD imported releases with `from` before `to`.
- get_investor_holdings / `entity` with an empty name matched every
  investor and returned an arbitrary one ("AMY"); `%` and `_` acted as
  LIKE wildcards. Reject empty names; match wildcards literally.
- Alias search never worked: the FTS table declared an `aliases` column
  its content table lacks (`no such column: T.aliases`), so searches
  fell back to canonical names and a raw KSEI name such as
  "PT ASTRA INTERNATIONAL TBK" found nothing. Search names and aliases
  directly, ranked exact name, exact alias, prefix, then shorter names.
- `graph` enumerated every path (exponential in depth) and its cycle
  check matched substrings, dropping entity:1 when entity:10 was on the
  path. Traverse breadth-first with an exact visited set.
- Name normalization removed leading PT tokens from the front of a Vec,
  quadratic in hostile names; narrow a slice instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V3syn2fN2LNo5pvTSqc6eh

crates/idx-mcp/tests/mcp.rs

@@ -394,6 +394,22 @@ fn ownership_tools_read_the_local_database() {
         assert!(page["next_offset"].is_null(), "offset {past}: {page}");
     }
 
+    // Bad, unknown, or reversed dates are errors, not "everyone is new".
+    for (from, to) in [
+        ("", "2026-02-27"),
+        ("1999-01-01", "2026-02-27"),
+        ("2026-02-27", "2026-01-30"),
+        ("2026-01-30", "2026-01-30"),
+    ] {
+        let (is_error, body) =
+            client.call("get_ownership_changes", json!({"from": from, "to": to}));
+        assert!(is_error, "{from}..{to}: {body}");
+        assert_eq!(body["code"], "INVALIDINPUT", "{from}..{to}: {body}");
+    }
+    let (is_error, body) = client.call("get_investor_holdings", json!({"entity": "  "}));
+    assert!(is_error, "{body}");
+    assert_eq!(body["code"], "INVALIDINPUT", "{body}");
+
     let (is_error, body) = client.call(
         "get_ownership_changes",
         json!({"from": "2026-01-30", "to": "2026-02-27", "limit": 301}),