test(cli): stop the registry plan check depending on the developer's machine

The test built a fixture with its own HOME and PATH, then asserted that
the whole install plan contained no path with "/plugins/" in it. Agent
detection does not stay inside HOME and PATH: cbm_find_cli also looks in
/usr/local/bin and, on macOS, /opt/homebrew/bin. A developer with OpenCode
installed there has it detected inside the fixture, and OpenCode ships a
real plugin file, so the plan legitimately carried a "/plugins/" path and
the assertion failed. On a machine without OpenCode the same assertion
passed, which is why CI never saw it.

Name the two directories the check actually meant — the fixture's Qoder
and Pi directories, neither of which has a plugin directory, so a planned
path under one would be invented. The check now tests the same thing
regardless of what the developer has installed.

No production behaviour changed. Searching well-known install directories
is deliberate, so that install finds an agent whose command is not on the
current PATH.

Fixes the failure at tests/test_cli.c:6859.
Local cli suite: 293 passed, 0 failed.

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

@@ -6561,8 +6561,19 @@ TEST(cli_agent_client_registry_routes_plan_install_and_uninstall) {
     char *plan = cbm_build_install_plan_json(tmpdir, binary_path);
     yyjson_doc *plan_doc = plan ? yyjson_read(plan, strlen(plan), 0) : NULL;
     yyjson_val *plan_root = plan_doc ? yyjson_doc_get_root(plan_doc) : NULL;
+    /* Neither of these agents has a plugin directory, so a planned path under
+     * one would be invented. Name the two directories rather than searching the
+     * whole plan for "/plugins/": OpenCode does ship a real plugin file, and
+     * agent detection finds a command in /usr/local/bin or /opt/homebrew/bin
+     * whatever HOME and PATH say, so a blanket search passes or fails according
+     * to what the developer happens to have installed. */
+    char qoder_plugins[700];
+    char pi_plugins[700];
+    snprintf(qoder_plugins, sizeof(qoder_plugins), "%s/plugins/", qoder_dir);
+    snprintf(pi_plugins, sizeof(pi_plugins), "%s/plugins/", pi_dir);
     bool plan_ok =
-        plan && !strstr(plan, "/plugins/") && !strstr(plan, "plugin_files") &&
+        plan && !strstr(plan, qoder_plugins) && !strstr(plan, pi_plugins) &&
+        !strstr(plan, "plugin_files") &&
         test_json_string_array_contains(plan_root, "config_files_planned", qoder_settings) &&
         test_json_string_array_contains(plan_root, "config_files_planned", amazon_config) &&
         test_json_string_array_contains(plan_root, "config_files_planned", roo_config) &&