chore: expose lib target + open-path profiling examples

Examples can't import from a bin-only crate, so add a thin lib.rs that
re-exports the existing modules. Used by the new examples that helped
diagnose the freeze fixed in the previous commit.

- examples/time_open: times parse / purge / cache / first-wires phases
- examples/inspect_insert: lists Insert blocks with sub-entity counts
- examples/find_raster: dumps RasterImage path + dimensions

Co-Authored-By: Claude Opus 4.7 <[email protected]>

examples/time_open.rs

@@ -0,0 +1,87 @@
+// Times each open phase: parse / purge / derived caches.
+// Run with:  cargo run --release --example time_open -- <path-to-dwg>
+
+use acadrust::entities::EntityType;
+use std::env;
+use std::path::Path;
+use std::time::Instant;
+use H7CAD::io::{load_file, purge_corrupt_entities};
+use H7CAD::scene::{build_derived_caches, Scene};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let path = env::args().nth(1).ok_or("usage: time_open <file>")?;
+
+    let t0 = Instant::now();
+    let mut doc = load_file(Path::new(&path))?;
+    let parse_ms = t0.elapsed().as_millis();
+
+    let t1 = Instant::now();
+    let dropped = purge_corrupt_entities(&mut doc);
+    let purge_ms = t1.elapsed().as_millis();
+
+    let t2 = Instant::now();
+    let caches = build_derived_caches(&doc);
+    let caches_ms = t2.elapsed().as_millis();
+
+    let mut counts = std::collections::HashMap::<&'static str, usize>::new();
+    let mut total = 0usize;
+    for e in doc.entities() {
+        total += 1;
+        let tag: &'static str = match e {
+            EntityType::Line(_) => "Line",
+            EntityType::Arc(_) => "Arc",
+            EntityType::Circle(_) => "Circle",
+            EntityType::LwPolyline(_) => "LwPolyline",
+            EntityType::Polyline2D(_) => "Polyline2D",
+            EntityType::Polyline3D(_) => "Polyline3D",
+            EntityType::Polyline(_) => "Polyline",
+            EntityType::Hatch(_) => "Hatch",
+            EntityType::Solid(_) => "Solid",
+            EntityType::RasterImage(_) => "RasterImage",
+            EntityType::Solid3D(_) => "Solid3D",
+            EntityType::Region(_) => "Region",
+            EntityType::Body(_) => "Body",
+            EntityType::Text(_) => "Text",
+            EntityType::MText(_) => "MText",
+            EntityType::Insert(_) => "Insert",
+            EntityType::Dimension(_) => "Dimension",
+            EntityType::Spline(_) => "Spline",
+            EntityType::Ellipse(_) => "Ellipse",
+            _ => "_other",
+        };
+        *counts.entry(tag).or_insert(0) += 1;
+    }
+    let mut counts: Vec<_> = counts.into_iter().collect();
+    counts.sort_by(|a, b| b.1.cmp(&a.1));
+
+    // Set up a Scene as the UI thread does and time first wire tessellation.
+    let mut scene = Scene::new();
+    scene.document = doc;
+    scene.world_offset = caches.world_offset;
+    scene.local_extent_max = caches.local_extent_max;
+    scene.hatches = caches.hatches.clone();
+    scene.images = caches.images.clone();
+    scene.meshes = caches.meshes.clone();
+    scene.bump_geometry();
+    scene.current_layout = "Model".to_string();
+    H7CAD::linetypes::populate_document(&mut scene.document);
+
+    let t3 = Instant::now();
+    let wires = scene.entity_wires();
+    let wires_ms = t3.elapsed().as_millis();
+
+    println!("file:           {}", path);
+    println!("parse:          {} ms", parse_ms);
+    println!("purge:          {} ms  (dropped {})", purge_ms, dropped);
+    println!("derived caches: {} ms", caches_ms);
+    println!("first wires:    {} ms  ({} wires)", wires_ms, wires.len());
+    println!("  hatches:      {}", caches.hatches.len());
+    println!("  images:       {}", caches.images.len());
+    println!("  meshes:       {}", caches.meshes.len());
+    println!();
+    println!("entities:       {}", total);
+    for (tag, n) in counts.iter().take(20) {
+        println!("  {:>14}  {}", tag, n);
+    }
+    Ok(())
+}