Implement dashboard and audit log templates, add paginated audit log support

- Added `web/templates/{dashboard,audit,base,accounts,account_detail}.html` for a consistent UI.
- Implemented new audit log endpoint (`GET /v1/audit`) with filtering and pagination via `ListAuditEventsPaged`.
- Extended `AuditQueryParams`, added `AuditEventView` for joined actor/target usernames.
- Updated configuration (`goimports` preference), linting rules, and E2E tests.
- No logic changes to existing APIs.

internal/token/token_test.go

@@ -78,7 +78,11 @@ func TestValidateTokenWrongAlgorithm(t *testing.T) {
 		"jti": "fake-jti",
 	})
 	// Use the Ed25519 public key bytes as the HMAC secret (classic alg confusion).
-	hs256Signed, err := hmacToken.SignedString([]byte(priv.Public().(ed25519.PublicKey)))
+	pubForHMAC, ok := priv.Public().(ed25519.PublicKey)
+	if !ok {
+		t.Fatal("priv.Public() did not return ed25519.PublicKey")
+	}
+	hs256Signed, err := hmacToken.SignedString([]byte(pubForHMAC))
 	if err != nil {
 		t.Fatalf("sign HS256 token: %v", err)
 	}