fix(lib): percent limits render as configured; xcelib_test counts every failure again

test_fmt_limit_units_percent_limit_ignores_units_mode failed on every
run: fmt_limit_units() widened the float limit value before scaling it,
so 0.8 printed as "80.000001%". The product is now taken in float and
widened after, which gives the configured 80.

The failure never counted: test_libxce_retry(), one group of test.c's
single runner, ran its own UNITY_BEGIN()/UNITY_END(), which reset Unity's
counters -- every failure in a group before it was dropped and
xcelib_test exited 0. With the pair removed the runner reports 695 tests;
this was the only hidden failure.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/lib/testsuite/test_libxce_retry.c

@@ -1847,9 +1847,11 @@ static void test_ff_call_is_single_shot_no_budget(void)
 
 /* ── Suite entry point ──────────────────────────────────────────────── */
 
+/* Runs inside test.c's single UNITY_BEGIN()/UNITY_END(). Its own pair
+ * reset Unity's counters, so every failure of a group run before this one
+ * was dropped from the final count and xcelib_test still exited 0. */
 void test_libxce_retry(void)
 {
-    UNITY_BEGIN();
     RUN_TEST(test_retry_defaults_are_reachable);
     RUN_TEST(test_fake_masters_hold_three_candidates);
     RUN_TEST(test_master_cursor_advances_and_wraps);
@@ -1906,5 +1908,4 @@ void test_libxce_retry(void)
     RUN_TEST(test_ff_call_is_single_shot_no_budget);
     RUN_TEST(test_decide_not_ready_backs_off_on_same_controller);
     RUN_TEST(test_retry_next_not_ready_does_not_rotate);
-    UNITY_END();
 }

src/lib/xcelimit.c

@@ -231,8 +231,11 @@ int fmt_limit_units(char* buf, int len, xce_limit_t* limit,
     }
 
     if (limit->val.percent != 0) {
+        /* val is a float: widen after scaling. 0.8f widened first is
+         * 0.800000011920929, which printed as "80.000001%"; the float
+         * product rounds to the 80 that was configured. */
         rc = snprintf(buf + pos, len - pos, "\n%s = %f%%\n",
-                      limit->val.resname, (double)limit->val.val * 100.0);
+                      limit->val.resname, (double)(limit->val.val * 100.0f));
     } else {
         bool is_swp = (limit->val.resname != NULL)
                       && (strcmp(limit->val.resname, "swp") == 0);