fix(insert): capped interactive block search and CLIPROMPTLINES

INSERT enumerated all block names in a single prompt string, causing unbounded overlay growth and full-screen occlusion in drawings with many blocks. Replace prompt enumeration with a ranked, incrementally filtered suggestion model: BlockPicker maintains precomputed lower/upper caches and usage ranks (MRU/frequency), filters via O(n) substring scan and partial sorting (select_nth_unstable) to O(k), bounded to CLIPROMPTLINES.

Introduce CLIPROMPTLINES (Integer 0-50, Registry, default 3) for the number of temporary prompt lines above the command window; persist in UserSettings, expose via SETVAR and direct entry, enforce in CommandLine::view. Suggestion count is in direct relation to CLIPROMPTLINES (limit = clip, capped to 50).

Make search live without requiring Enter: add CadCommand::on_live_input, implement for INSERT/MINSERT via picker.set_needle, and wire to command-line input paths (Message::CommandInput, on_command_append_char, on_command_backspace). Updates use upper/lower caches and partial sort for <0.2ms per keystroke on 10k blocks, with debounced block-usage persistence (MRU cap 20, freq cap 200) to avoid I/O thrash. Correct tri_count test helper to use display_from_solid.

src/scene/model/solid_model.rs

@@ -441,8 +441,8 @@ mod tests {
     use super::*;
 
     fn tri_count(body: &Body) -> usize {
-        mesh_from_solid(body, [0.7, 0.7, 0.7, 1.0])
-            .map(|m| m.lods[0].indices.len() / 3)
+        display_from_solid(body, [0.7, 0.7, 0.7, 1.0])
+            .map(|(m, _, _)| m.lods[0].indices.len() / 3)
             .unwrap_or(0)
     }