fix: support go-getter URLs in ad-hoc dependencies to fix #821 (#2670)

* fix: support go-getter URLs in ad-hoc dependencies to fix #821

Ad-hoc release dependencies (release.dependencies[].chart) that used
go-getter URLs like "git::https://host/repo.git@path?ref=tag" were passed
to chartify as-is. chartify then tried to resolve them via `helm repo
list`, which fails with "no helm list entry found for repository
\"git::https:\". please `helm repo add` it!".

The primary chart already fetched such URLs via downloadChartWithGoGetter,
but the ad-hoc dependency path in PrepareChartify only handled local
directories and OCI rewrites, so go-getter URLs fell through.

This adds a branch that detects remote go-getter URLs (remote.IsRemote)
and fetches them to a local cache directory via a new
downloadAdhocDepChartWithGoGetter helper, mirroring the primary-chart
fetch path. chartify then sees a local chart and takes its file:// branch.

Fixes #821

Signed-off-by: yxxhero <aiopsclub@163.com>

* test: add integration test for go-getter ad-hoc dependencies (#821)

Adds an integration test that commits a chart to a throwaway local git repo
and references it via a "git::file://..." go-getter URL as a release
ad-hoc dependency, then asserts `helmfile template` renders both the main
chart and the fetched dependency.

Using file:// (rather than https://) keeps the test deterministic and
network-free while exercising the exact fix path (remote.IsRemote +
downloadAdhocDepChartWithGoGetter in PrepareChartify). Verified to fail on
the unfixed code with the original "no helm list entry found for repository
\"git::file:\"" error and pass on the fixed code.

Signed-off-by: yxxhero <aiopsclub@163.com>

* test: surface helmfile error in issue #821 integration test

The integration runner (run.sh) enables `set -e`, so a non-zero helmfile
exit aborted the script before the captured output could be printed,
hiding the real failure in CI. Disable `set -e` around the helmfile
invocation and report the exit code plus full output on failure.

Signed-off-by: yxxhero <aiopsclub@163.com>

* test: fix issue-821 integration test chart path and errexit handling

Two issues caused the integration test to fail in CI (while passing in my
local smoke test, which used an absolute path):

1. The main chart path was relative to the integration CWD, but the
   helmfile.yaml is generated in a temp directory and helmfile resolves
   `chart:` relative to that directory (its basePath). The relative path
   was interpreted as a named-repo chart and failed instantly with
   `Error: repo test not found`. Resolve the case dir to an absolute path
   with `$(cd ... && pwd)`.

2. run.sh runs under `set -e`, so the unguarded helmfile invocation exited
   the whole script on failure before the captured output could be printed,
   hiding the real error. Capture the exit code via `cmd || rc=$?` so
   failures are reported.

Signed-off-by: yxxhero <aiopsclub@163.com>

---------

Signed-off-by: yxxhero <aiopsclub@163.com>

test/integration/run.sh

@@ -144,6 +144,7 @@ ${kubectl} create namespace ${test_ns} || fail "Could not create namespace ${tes
 . ${dir}/test-cases/issue-2431.sh
 . ${dir}/test-cases/issue-2544.sh
 . ${dir}/test-cases/issue-2596-local-deps-multiple-files.sh
+. ${dir}/test-cases/issue-821-adhoc-dep-go-getter.sh
 . ${dir}/test-cases/issue-2599-default-inherit.sh
 . ${dir}/test-cases/kubedog-tracking.sh
 . ${dir}/test-cases/lookup.sh