feat: ordered multi-file Compose for Git sources (#1380)

* feat: ordered multi-file Compose for Git sources

Extend Git sources to deploy an ordered list of compose files merged with
docker compose -f base.yaml -f override.yaml ..., plus an optional project
directory.

- Pick and reorder compose files from the repository tree (drag to reorder on
  desktop, up/down arrows on phones); manual path entry is also supported.
- The ordered set drives every stack-scoped compose command (deploy, update,
  start/stop/restart/down, image scans, Compose Doctor) and the container
  lookup, so a service or image declared only in an override is handled too.
- Runtime keys off the materialized set, not the saved configuration: saving a
  source does not change deploy args until the pull is applied, and apply
  materializes from the pending snapshot rather than live config.
- The project directory is passed as --project-directory, with -p <stack>
  pinning the Compose project so container labels stay stable.
- The Mesh override is layered last; single-file sources are byte-identical to
  before, and existing rows keep working via the single-path fallback.

Docs cover the picker, ordering, project directory, and the new troubleshooting
and limitations (referenced files are not materialized; the dependency graph,
drift, and networking views read the primary file).

* fix: harden multi-file Git source (hash, unlink, collisions, node id)

- hashContent folds ordered file CONTENTS (not paths) so a clean multi-file
  stack is not flagged as locally edited: create/apply hash the fetched files
  (repo paths) while pull hashes the on-disk files (materialized paths), which
  previously disagreed and showed a false "local edits detected".
- Block unlinking a multi-file or project-directory Git source (409): the deploy
  spec lives on the source row, so removing it would silently revert deploys to
  root compose.yaml. Single-file sources still unlink.
- Reject materialized-path collisions in the selection validator: an additional
  file equal to or nested under compose.yaml, an ancestor/descendant overlap
  between selected files, and a project directory nested under a compose file
  (previously a 500 at materialization).
- DockerController.getContainersByStack uses the controller's node compose dir
  and passes its node id to the authored prefix, instead of the process default.

* fix: CI failures on multi-file Git source (test crash, aria query, path barrier)

- GitSourceFields no longer crashes when repoUrl/branch are falsy: the canBrowse
  trim() is optional-chained, so a reusable field component tolerates partial
  props. Fixes the apply-binding panel test, which feeds a minimal source object.
- GitSourcePanel tests query the footer Remove button by its exact name, so the
  picker's per-file "Remove <path>" buttons no longer collide with the broad
  /remove/i match (the test intent, footer Remove present/absent, is unchanged).
- validateCompose uses an inline resolve + startsWith barrier at the context-dir
  mkdir sink (CodeQL does not credit the wrapped isPathWithinBase helper),
  clearing the js/path-injection alert. The containment check is equivalent and
  contextDir is also validated upstream.

* test: update Git source E2E spec for the multi-file compose picker

The compose-file picker replaced the single #git-source-path input and added
per-file Remove buttons, so the E2E spec drove selectors that no longer exist:

- Drop the redundant compose.yaml fills (the picker defaults to compose.yaml).
- Select the footer Remove button by exact name so the picker's per-file
  "Remove <path>" buttons no longer make the locator ambiguous.
- Set a custom compose path through the picker (add via the manual input, press
  Enter, then remove the default compose.yaml).

* test: match the footer Remove button with an exact Playwright name

Playwright's getByRole name option is a substring match by default, so
{ name: 'Remove' } also matched the picker's "Remove <path>" buttons. Require an
exact match so only the footer Remove button is selected.

e2e/git-sources.spec.ts

@@ -68,8 +68,6 @@ test.describe('Git Sources', () => {
 
     await page.locator('#git-source-repo').fill('git@github.com:org/repo.git');
     await page.locator('#git-source-branch').fill('main');
-    await page.locator('#git-source-path').fill('compose.yaml');
-
     await page.getByRole('dialog').getByRole('button', { name: /^Save$/ }).click();
 
     await expect(page.getByText(/Only HTTPS repository URLs are supported/i)).toBeVisible({ timeout: 5_000 });
@@ -83,8 +81,6 @@ test.describe('Git Sources', () => {
     // which maps to NETWORK_TIMEOUT or REPO_NOT_FOUND.
     await page.locator('#git-source-repo').fill('https://git.invalid.example/nope/nope.git');
     await page.locator('#git-source-branch').fill('main');
-    await page.locator('#git-source-path').fill('compose.yaml');
-
     await page.getByRole('dialog').getByRole('button', { name: /^Save$/ }).click();
 
     // Any of the mapped error messages is acceptable; the key is that nothing
@@ -191,8 +187,10 @@ test.describe('Git Sources', () => {
     // Source should render with the saved repo URL.
     await expect(page.locator('#git-source-repo')).toHaveValue(/awesome-compose/);
 
-    // Click Remove → AlertDialog appears → confirm → source cleared.
-    await page.getByRole('dialog').getByRole('button', { name: /Remove/i }).click();
+    // Click Remove → AlertDialog appears → confirm → source cleared. Playwright's
+    // name match is substring by default, so require an exact match to select the
+    // footer button and not the picker's per-file "Remove <path>" buttons.
+    await page.getByRole('dialog').getByRole('button', { name: 'Remove', exact: true }).click();
     await expect(page.getByRole('alertdialog')).toBeVisible({ timeout: 5_000 });
     await page.getByRole('alertdialog').getByRole('button', { name: /^Remove$/ }).click();
 
@@ -249,8 +247,6 @@ test.describe('Create stack from Git', () => {
     await page.locator('#create-git-stack-name').fill(CREATE_FROM_GIT_STACK);
     await page.locator('#git-source-repo').fill('git@github.com:org/repo.git');
     await page.locator('#git-source-branch').fill('main');
-    await page.locator('#git-source-path').fill('compose.yaml');
-
     await page.getByRole('dialog').getByRole('button', { name: /Create from Git/i }).click();
     await expect(page.getByText(/Only HTTPS repository URLs are supported/i)).toBeVisible({ timeout: 5_000 });
   });
@@ -365,7 +361,12 @@ test.describe('Create stack from Git', () => {
       await page.locator('#create-git-stack-name').fill(uiName);
       await page.locator('#git-source-repo').fill('https://github.com/docker/awesome-compose.git');
       await page.locator('#git-source-branch').fill('master');
-      await page.locator('#git-source-path').fill('nginx-golang/compose.yaml');
+      // Drive the compose-file picker: add the repo path, then drop the default
+      // compose.yaml so only the intended file is deployed.
+      const createDialog = page.getByRole('dialog');
+      await createDialog.getByPlaceholder('path/to/compose.yaml').fill('nginx-golang/compose.yaml');
+      await createDialog.getByPlaceholder('path/to/compose.yaml').press('Enter');
+      await createDialog.getByRole('button', { name: 'Remove compose.yaml' }).click();
 
       await page.getByRole('dialog').getByRole('button', { name: /Create from Git/i }).click();