fix: isolate integration tests from host repo git config

lib/wt-common

@@ -94,6 +94,10 @@ wt_read_context_config() {
 # Returns: 0 if config was loaded, 1 if not (not in repo, not enabled,
 #          no keys, or incomplete config).
 wt_read_git_config() {
+  # Allow tests to skip git config loading to avoid picking up the host repo's config.
+  # This follows the same pattern as _wt_is_interactive override in lib/wt-adopt.
+  [[ -n "${_WT_SKIP_GIT_CONFIG:-}" ]] && return 1
+
   # Only proceed if we're inside a git repo or worktree
   local repo_root
   repo_root="$(git rev-parse --show-toplevel 2>/dev/null)" || return 1

test/test_helper/common.bash

@@ -45,6 +45,7 @@ setup_test_env() {
     export PATH="$TEST_HOME/.wt/bin:$PATH"
     export _WT_ROOT="$TEST_HOME/.wt"
     export LIB_DIR="$TEST_HOME/.wt/lib"
+    export _WT_SKIP_GIT_CONFIG=1
 }
 
 # Teardown test environment

test/unit/wt-common.bats

@@ -8,6 +8,11 @@ setup() {
 
     # Source the library under test
     source "$TEST_HOME/.wt/lib/wt-common"
+
+    # Re-enable wt_read_git_config for unit tests that exercise it directly.
+    # The guard was needed during source-time to prevent host repo config bleed,
+    # but unit tests cd into their own mock repos before calling the function.
+    unset _WT_SKIP_GIT_CONFIG
 }
 
 teardown() {