test(cli): point PATH at the fixture so uninstall isolation holds on any machine

cli_uninstall_quiesces_active_cohort_before_removing_binary_and_index moved
HOME and CBM_CACHE_DIR into a temporary directory but left PATH alone. Agent
detection reads PATH first, so a real agent binary on the developer's machine
was found even though HOME pointed at the empty fixture. Uninstall then tried
to edit that agent's config file inside the fixture, failed because the fixture
never created one, and stopped before removing the binary and the index. The
test measures exactly that removal, so it failed.

On this machine the agent is Goose, at /Users/<me>/go/bin/goose. Same tree and
same built runner, only PATH differs:

  goose on PATH        291 passed, 1 failed
  goose off PATH       292 passed, 0 failed

With this change the suite reports 292 passed, 0 failed while goose is still on
PATH, so the fix is the redirect and not a quieter environment.

This only stops the suite from depending on what the developer has installed.
The abort it exposed is a real defect and is reported in DeusData#1954: one agent config
that cannot be edited stops teardown for every other agent and for the
executable and indexes.

Eleven other tests that call cli_activation_save_env leave PATH open the same
way. They pass today, so I left them alone rather than change what they
exercise without evidence.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Joshua Richter <jrichter5781@gmail.com>

Author: CaptainMittens

tests/test_cli.c

@@ -1707,6 +1707,15 @@ TEST(cli_uninstall_quiesces_active_cohort_before_removing_binary_and_index) {
     char *old_cache = NULL;
     cli_activation_save_env(&old_home, &old_cache);
     cbm_setenv("HOME", tmpdir, 1);
+    /* PATH has to move with HOME. Agent detection asks cbm_find_cli, which
+     * reads PATH before anything else, so a real agent binary on the developer's
+     * PATH is found even though HOME points at this fixture. Uninstall then
+     * tries to edit that agent's config file here, fails because the fixture
+     * never created one, and stops before removing the binary and the index —
+     * which is exactly what this test measures. Redirecting PATH makes the
+     * result the same on every machine. */
+    char *old_path = save_test_env("PATH");
+    cbm_setenv("PATH", tmpdir, 1);
 
     char cache_dir[512];
     char index_path[640];
@@ -1744,6 +1753,7 @@ TEST(cli_uninstall_quiesces_active_cohort_before_removing_binary_and_index) {
     bool binary_preserved =
         installed && strcmp(installed, "binary must survive active-daemon refusal") == 0;
     cli_activation_restore_env(old_home, old_cache);
+    restore_test_env("PATH", old_path);
     test_rmdir_r(tmpdir);
 
     ASSERT_EQ(rc, 0);