perf(fleet): scan persona dirs once per provision

Fix #665 test timeout.

packages/mosaic/src/commands/fleet-personas.ts

@@ -234,6 +234,21 @@ export async function resolvePersona(
     extractClassesFromDir(rolesDir),
     extractClassesFromDir(overrideDir),
   ]);
+  return resolvePersonaFrom(klass, { rolesDir, overrideDir, base, over });
+}
+
+/**
+ * Resolve a single class against ALREADY-EXTRACTED layer maps. Callers that
+ * resolve many classes against the same two directories (e.g. provisioning a
+ * full roster) should {@link extractClassesFromDir} each dir ONCE and reuse the
+ * result here, rather than paying a full directory re-scan per class. Precedence
+ * is identical to {@link resolvePersona}: override layer wins, then baseline.
+ */
+export async function resolvePersonaFrom(
+  klass: string,
+  layers: { rolesDir: string; overrideDir: string; base: DirClasses; over: DirClasses },
+): Promise<PersonaResolution | null> {
+  const { rolesDir, overrideDir, base, over } = layers;
 
   const fromLayer = async (
     dir: string,

packages/mosaic/src/commands/fleet-provision.ts

@@ -33,7 +33,12 @@ import {
   defaultRolesDir,
   listPersonaClassesWithOverrides,
 } from './fleet-profiles.js';
-import { defaultOverrideDir, resolvePersona, type PersonaLayer } from './fleet-personas.js';
+import {
+  defaultOverrideDir,
+  extractClassesFromDir,
+  resolvePersonaFrom,
+  type PersonaLayer,
+} from './fleet-personas.js';
 
 function defaultMosaicHome(): string {
   return process.env['MOSAIC_HOME'] ?? join(homedir(), '.config', 'mosaic');
@@ -172,12 +177,21 @@ export async function generateRoster(
     ? profile.roster
     : profile.roster.filter((e) => floor.has(e.class));
 
+  // Scan the persona directories ONCE, then resolve every roster entry against
+  // the in-memory maps. resolvePersona() would otherwise re-scan both dirs per
+  // entry — O(entries × files) redundant reads that push --full provisioning
+  // past the test timeout on slow/contended filesystems.
+  const [base, over] = await Promise.all([
+    extractClassesFromDir(rolesDir),
+    extractClassesFromDir(overrideDir),
+  ]);
+
   const seats: GeneratedSeat[] = [];
   for (const entry of selected) {
     const isFloor = floor.has(entry.class);
     const isLead = entry.class === lead;
 
-    const resolved = await resolvePersona(entry.class, { rolesDir, overrideDir });
+    const resolved = await resolvePersonaFrom(entry.class, { rolesDir, overrideDir, base, over });
     if (!resolved) {
       // Defensive: validateProfile already guards this, but a class can resolve
       // for membership yet have no readable file. Fail loudly rather than emit a