test: add vitest with supply + http unit tests, wire into CI

22 tests covering the FairCoin supply schedule (premine, halvings, hard
cap, monotonicity) and the route validation helpers (parseNetwork,
parseLimit, parseOffset, parseAddress, escapeRegex). The CI workflow
runs them via bun and switches off the npm setup that didn't match the
project's bun.lock.

Author: NateIsern

.github/workflows/ci.yml

@@ -8,24 +8,26 @@ on:
 
 jobs:
   build:
-    name: Typecheck & Build
+    name: Typecheck, Test & Build
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-node@v4
+      - uses: oven-sh/setup-bun@v2
         with:
-          node-version: 22
-          cache: npm
+          bun-version: latest
 
       - name: Install dependencies
-        run: npm ci
+        run: bun install --frozen-lockfile
 
       - name: Typecheck (frontend + server)
-        run: npm run typecheck
+        run: bun run typecheck
+
+      - name: Test
+        run: bun run test
 
       - name: Build frontend
-        run: npm run build
+        run: bun run build
 
       - name: Check i18n locale key parity
         run: |