Add Playwright/bootRun/test.sh tasks (#6244)

## Description

Consolidates Playwright running under cohesive Task namespaces, isolates
Playwright state from the developer's local working tree, and swaps CI's
frontend webserver from `vite` dev to `vite preview` against a pre-built
`dist/`.

### `e2e:*` namespace

Renames `.taskfiles/testing.yml` to `.taskfiles/e2e.yml` and
consolidates everything Playwright-related under one `e2e:` namespace:

- `e2e:stubbed` / `e2e:live` / `e2e:enterprise` / `e2e:cross-browser`:
project-specific runners
- `e2e:check` (no-Docker subset) and `e2e:check:all` (full)
- `e2e:oauth:up` / `:down`, `e2e:saml:up` / `:down`: symmetric lifecycle
for the keycloak compose stacks
- `e2e:install`: Playwright browser install
- `docker:test`: full Docker integration suite

The redundant `frontend:test:e2e:*` project shortcuts are removed. CI
workflows (`e2e-stubbed.yml`, `e2e-live.yml`, `build-enterprise.yml`,
`nightly.yml`) are updated to call the new task names.

### Isolated Playwright state

New `STIRLING_BASE_PATH` (and `-Dstirling.base-path=`) override in
`InstallationPathConfig` redirects the entire state tree (configs,
backups, customFiles, pipeline, logs) at startup. `task e2e:live` points
it at `.test-state/playwright/` (purged on every invocation) so the
suite never touches the developer's local DB, settings.yml or backups.

`task e2e:live` auto-spawns gradle, waits for `/api/v1/info/status` to
come up, runs Playwright, then tears down the whole backend process
tree.

### CI runs Playwright against `vite preview`

Builds the frontend up-front with `VITE_BUILD_FOR_PREVIEW=1` (forces
absolute base so deep SPA routes resolve `/assets/...`) and the
playwright `webServer` now uses `vite preview --port 5173 --strictPort`
in CI. Avoids the per-page on-demand transform cost that was blowing the
30s navigation timeout under `--workers=3` on
`all-tool-pages-load.spec.ts`. Local dev keeps `vite` dev for HMR.

### OAuth/SAML compose helpers

`start-oauth-test.sh` and `start-saml-test.sh` gain a `--license-key
<KEY>` (`-k`) flag so CI and scripted runs can skip the interactive
license prompt. `start-oauth-test.sh` also moves from `for arg in "$@"`
to a `while`-with-`shift` arg loop to support multi-arg flags
consistently with the SAML script.

### Backend gradlew unification

Drops the per-platform `cmd /c gradlew.bat` branches from `backend.yml`
and routes every gradle invocation through `bash gradlew`. Works
uniformly on Linux/macOS and Windows-with-Git-Bash.

### Compare.tsx flake fix (re-land of
[#6316](https://github.com/Stirling-Tools/Stirling-PDF/pull/6316))

Piggybacks Anthony's never-merged fix from #6316. Without it,
`e2e:stubbed` continues to flake under `--workers=3` on
`compare.spec.ts`'s second-upload case via a React "Maximum update depth
exceeded" infinite loop in the Compare auto-fill effect. CI traces from
recent failed runs match exactly; 10 local runs of `compare.spec.ts`
with `CI=1 --workers=3` pass cleanly with the fix applied.

---------

Co-authored-by: James Brunton <[email protected]>

frontend/vite.config.ts

@@ -49,6 +49,21 @@ export default defineConfig(async ({ mode }) => {
     xfwd: true,
   };
 
+  // Shared between `vite` (dev) and `vite preview` (production-build serve, used
+  // in CI/E2E) so the live test suite still resolves /api → :8080.
+  const backendProxyConfig =
+    effectiveMode === "desktop"
+      ? undefined
+      : {
+          "/api": backendProxy,
+          "/oauth2": backendProxy,
+          "/saml2": backendProxy,
+          "/login/oauth2": backendProxy,
+          "/login/saml2": backendProxy,
+          "/swagger-ui": backendProxy,
+          "/v1/api-docs": backendProxy,
+        };
+
   return {
     plugins: [
       react(),
@@ -107,19 +122,25 @@ export default defineConfig(async ({ mode }) => {
         ignored: ["**/src-tauri/**"],
       },
       // Only use proxy in web mode - Tauri handles backend connections directly
-      proxy:
-        effectiveMode === "desktop"
-          ? undefined
-          : {
-              "/api": backendProxy,
-              "/oauth2": backendProxy,
-              "/saml2": backendProxy,
-              "/login/oauth2": backendProxy,
-              "/login/saml2": backendProxy,
-              "/swagger-ui": backendProxy,
-              "/v1/api-docs": backendProxy,
-            },
+      proxy: backendProxyConfig,
     },
-    base: env.RUN_SUBPATH ? `/${env.RUN_SUBPATH}` : "./",
+    preview: {
+      host: true,
+      port: 5173,
+      strictPort: true,
+      proxy: backendProxyConfig,
+    },
+    // base: "./" produces relative asset URLs which work when dist/ is served
+    // at any path (e.g. Spring Boot bundling the frontend at /). But under
+    // `vite preview` for deep SPA routes (e.g. /workflow/sign/<token>), the
+    // browser resolves ./assets/X.js relative to the current path → 404, then
+    // SPA fallback returns index.html as text/html and React never mounts.
+    // VITE_BUILD_FOR_PREVIEW=1 (set by the CI playwright steps) overrides to
+    // an absolute base so deep-route asset paths resolve to /assets/...
+    base: env.RUN_SUBPATH
+      ? `/${env.RUN_SUBPATH}`
+      : process.env.VITE_BUILD_FOR_PREVIEW === "1"
+        ? "/"
+        : "./",
   };
 });