fix(cli): sanitize errors and diagnostics at their choke points

From the narrow Codex confirmation: provider, KSEI, and manifest text
still reached the terminal through error messages (a Yahoo error
description, a manifest's `kind`), idx-core diagnostics, the ownership
heading's ticker code and Bing date, the technical heading and
comparison symbol, and printed paths. Sanitize where every error
(emit_error) and every diagnostic (runtime) is printed instead of at each
caller, plus the remaining direct prints. terminal_safe moves to
idx_core::text so the runtime can use it; the CLI re-exports it.

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

crates/idx-core/src/lib.rs

@@ -15,6 +15,7 @@ pub mod investor;
 pub mod market;
 #[cfg(feature = "ownership")]
 pub mod ownership;
+pub mod text;
 
 pub use client::{CachePolicy, Fetched, Idx};
 
@@ -47,7 +48,10 @@ pub mod runtime {
             let line = serde_json::json!({ "level": level, "message": message.to_string() });
             eprintln!("{line}");
         } else {
-            eprintln!("{level}: {message}");
+            eprintln!(
+                "{level}: {}",
+                crate::text::terminal_safe(&message.to_string())
+            );
         }
     }