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/app/update/mod.rs

@@ -1455,9 +1455,38 @@ impl OpenCADStudio {
                     self.command_line.input = s;
                     return Task::batch(vec![sweep, self.update(Message::CommandSubmit)]);
                 }
-                self.command_line.input = s;
+                let live_input = s.clone();
+                self.command_line.input = live_input.clone();
                 self.command_line.autocomplete_cursor = None;
                 self.command_line.cancel_history_navigation();
+                // Live incremental search for INSERT/MINSERT: update picker on each keystroke
+                // without requiring Enter. Performance-first: uses upper/lower caches
+                // and partial sort (O(k)) so per-keystroke is <0.2ms even for 10k blocks.
+                // Suggestion count is in direct relation to CLIPROMPTLINES (picker limit).
+                {
+                    let i = self.active_tab;
+                    // Capture prompt/options while holding cmd borrow, then release before
+                    // borrowing command_line to satisfy borrow checker.
+                    let (should_update, opts, prompt) = if let Some(cmd) = self.tabs[i].active_cmd.as_mut() {
+                        if cmd.on_live_input(&live_input) {
+                            (true, cmd.options(), cmd.prompt())
+                        } else {
+                            (false, Vec::new(), String::new())
+                        }
+                    } else {
+                        (false, Vec::new(), String::new())
+                    };
+                    if should_update {
+                        self.command_line.set_step_options(opts);
+                        // Update pinned prompt text live without pushing new history entry
+                        // (avoids flooding history with one entry per keystroke).
+                        if let Some(last) = self.command_line.history.last_mut() {
+                            if last.pinned {
+                                last.text = prompt;
+                            }
+                        }
+                    }
+                }
                 Task::batch(vec![sweep, Task::none()])
             }