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]>

testing/compose/start-oauth-test.sh

@@ -15,27 +15,52 @@ echo ""
 AUTO_LOGIN=false
 FORCE_ALL_LOGIN=false
 COMPOSE_UP_ARGS=(-d --build)
-for arg in "$@"; do
-    case "$arg" in
+while [[ $# -gt 0 ]]; do
+    case "$1" in
         --auto)
             AUTO_LOGIN=true
+            shift
             ;;
         --all)
             FORCE_ALL_LOGIN=true
+            shift
             ;;
         --nobuild)
             COMPOSE_UP_ARGS=(-d)
+            shift
+            ;;
+        --license-key)
+            if [[ -z "${2:-}" ]]; then
+                echo -e "${RED}Missing value for --license-key${NC}"
+                exit 1
+            fi
+            export PREMIUM_KEY="$2"
+            shift 2
+            ;;
+        --license-key=*)
+            export PREMIUM_KEY="${1#*=}"
+            shift
+            ;;
+        -k)
+            if [[ -z "${2:-}" ]]; then
+                echo -e "${RED}Missing value for -k${NC}"
+                exit 1
+            fi
+            export PREMIUM_KEY="$2"
+            shift 2
             ;;
         -h|--help)
-            echo "Usage: $0 [--auto] [--nobuild]"
+            echo "Usage: $0 [--auto] [--all] [--nobuild] [--license-key <KEY>]"
             echo ""
-            echo "  --auto     Enable SSO auto-login and force OAuth-only login method"
-            echo "  --all      Force login method to allow all providers (overrides --auto)"
-            echo "  --nobuild  Skip building images (use existing images)"
+            echo "  --auto                Enable SSO auto-login and force OAuth-only login method"
+            echo "  --all                 Force login method to allow all providers (overrides --auto)"
+            echo "  --nobuild             Skip building images (use existing images)"
+            echo "  --license-key <KEY>   Premium license key (skips the interactive prompt)"
+            echo "                        Equivalent to setting PREMIUM_KEY in the environment."
             exit 0
             ;;
         *)
-            echo -e "${RED}Unknown option: $arg${NC}"
+            echo -e "${RED}Unknown option: $1${NC}"
             exit 1
             ;;
     esac

testing/compose/start-saml-test.sh

@@ -55,14 +55,36 @@ while [[ $# -gt 0 ]]; do
             DEFAULT_LANGUAGE="$2"
             shift 2
             ;;
+        --license-key)
+            if [[ -z "${2:-}" ]]; then
+                echo -e "${RED}Missing value for --license-key${NC}"
+                exit 1
+            fi
+            export PREMIUM_KEY="$2"
+            shift 2
+            ;;
+        --license-key=*)
+            export PREMIUM_KEY="${1#*=}"
+            shift
+            ;;
+        -k)
+            if [[ -z "${2:-}" ]]; then
+                echo -e "${RED}Missing value for -k${NC}"
+                exit 1
+            fi
+            export PREMIUM_KEY="$2"
+            shift 2
+            ;;
         -h|--help)
-            echo "Usage: $0 [--auto] [--with-storage] [--nobuild] [--language <locale>]"
+            echo "Usage: $0 [--auto] [--with-storage] [--nobuild] [--language <locale>] [--license-key <KEY>]"
             echo ""
-            echo "  --auto          Enable SSO auto-login and force SAML-only login method"
-            echo "  --with-storage  Enable the file storage + link-sharing feature"
-            echo "                  (required to test /share/<token> flows)"
-            echo "  --nobuild       Skip building images (use existing images)"
-            echo "  --language      Set system default locale (e.g. de-DE, sv-SE)"
+            echo "  --auto                Enable SSO auto-login and force SAML-only login method"
+            echo "  --with-storage        Enable the file storage + link-sharing feature"
+            echo "                        (required to test /share/<token> flows)"
+            echo "  --nobuild             Skip building images (use existing images)"
+            echo "  --language            Set system default locale (e.g. de-DE, sv-SE)"
+            echo "  --license-key <KEY>   Premium license key (skips the interactive prompt)"
+            echo "                        Equivalent to setting PREMIUM_KEY in the environment."
             exit 0
             ;;
         *)