feat: Add smart density defaults based on material type (#2)

Auto-fill density when entering material type in filament forms:
- Add materialDefaults.ts with standard densities for common materials
  (PLA, ABS, PETG, TPU, PC, etc.)
- Material field now uses AutoComplete with suggestions
- Density auto-fills on material select or blur (fuzzy matching)
- New filaments default to 1.75mm diameter and 1.24 g/cm³ (PLA)
- Applied to both full filament create page and quick create modal

Reduces tedious data entry for common materials while still allowing
custom values for specialty filaments.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/src/utils/materialDefaults.ts

@@ -0,0 +1,90 @@
+/**
+ * Standard material densities for common 3D printing filaments.
+ * Values are in g/cm³.
+ *
+ * Reference: https://www.simplify3d.com/resources/materials-guide/
+ */
+export const MATERIAL_DENSITY_MAP: Record<string, number> = {
+  PLA: 1.24,
+  ABS: 1.04,
+  PETG: 1.27,
+  NYLON: 1.52,
+  TPU: 1.21,
+  PC: 1.3,
+  WOOD: 1.28,
+  CF: 1.3,
+  "PC/ABS": 1.19,
+  HIPS: 1.03,
+  PVA: 1.23,
+  ASA: 1.05,
+  PP: 0.9,
+  POM: 1.4,
+  PMMA: 1.18,
+  FPE: 2.16,
+};
+
+/**
+ * Default filament diameter in mm (most common standard).
+ */
+export const DEFAULT_DIAMETER = 1.75;
+
+/**
+ * Default density in g/cm³ (PLA, most common material).
+ */
+export const DEFAULT_DENSITY = 1.24;
+
+/**
+ * List of known materials for AutoComplete suggestions.
+ */
+export const KNOWN_MATERIALS = Object.keys(MATERIAL_DENSITY_MAP);
+
+/**
+ * Get the density for a material type using fuzzy matching.
+ * Handles variations like "PLA Silk", "PETG-CF", "Wood PLA", etc.
+ *
+ * @param material - The material string to look up
+ * @returns The density if a match is found, undefined otherwise
+ */
+export function getDensityForMaterial(material: string | undefined): number | undefined {
+  if (!material) return undefined;
+
+  const normalizedInput = material.toUpperCase().trim();
+
+  // Exact match first
+  if (MATERIAL_DENSITY_MAP[normalizedInput]) {
+    return MATERIAL_DENSITY_MAP[normalizedInput];
+  }
+
+  // Fuzzy match: check if input starts with or contains a known material
+  // Sort by length descending to match longer patterns first (e.g., "PC/ABS" before "PC")
+  const sortedMaterials = KNOWN_MATERIALS.sort((a, b) => b.length - a.length);
+
+  for (const knownMaterial of sortedMaterials) {
+    // Check if the input starts with the material (e.g., "PLA Silk" starts with "PLA")
+    if (normalizedInput.startsWith(knownMaterial)) {
+      return MATERIAL_DENSITY_MAP[knownMaterial];
+    }
+    // Check if the input contains the material as a word boundary
+    // This handles cases like "Wood PLA" or "CF-PETG"
+    const regex = new RegExp(`\\b${knownMaterial}\\b`, "i");
+    if (regex.test(normalizedInput)) {
+      return MATERIAL_DENSITY_MAP[knownMaterial];
+    }
+  }
+
+  return undefined;
+}
+
+/**
+ * Filter materials for AutoComplete based on input.
+ * Returns materials that contain the search string (case-insensitive).
+ *
+ * @param searchValue - The search string
+ * @returns Filtered list of material suggestions
+ */
+export function filterMaterials(searchValue: string): string[] {
+  if (!searchValue) return KNOWN_MATERIALS;
+
+  const normalizedSearch = searchValue.toUpperCase().trim();
+  return KNOWN_MATERIALS.filter((material) => material.includes(normalizedSearch));
+}