Portal (#6391)

# Description of Changes

## What & why

This PR introduces the **Stirling developer portal** — a new
control-plane frontend that sits alongside the existing PDF editor —
plus the shared design system and workspace structure needed to host
both apps in one frontend.

The portal is the parent product surface: where users connect sources,
compose pipelines, wire agents, and manage usage / billing /
infrastructure, with the PDF editor as one capability inside it. This PR
lays the **foundation** — workspace reshape, design system, app shell,
navigation, and a mock-driven home — rather than wiring real backends
(those surfaces are placeholders for follow-up phases).

## What's in this PR

**1. Frontend repo reshape (`frontend/src/` → `frontend/editor/`)**
The existing editor app moved under `frontend/editor/`, so `editor`,
`portal`, and `shared` are siblings in one workspace. All references
were updated accordingly: `LICENSE`, `.dockerignore`, `.gitignore`,
build/sign shell scripts, the GH language-check script, the Taskfile,
and Docker config. **No editor source logic changed — path references
only.**

**2. New shared design system (`frontend/shared/`)**
- **Design tokens** in `tokens.css` as the single runtime source of
truth (light/dark, category accents, gradients). `tokens.ts` now holds
only the `Tier` type — the old JS palette mirror was removed (nothing
consumed it and it had drifted).
- ~30 framework-light **components** (Card, Button, Input, Select, Tabs,
Modal, Drawer, Toast, MetricCard, StatusBadge, Skeleton, EmptyState, …)
with Storybook stories.
- **Typed data catalogues**: `endpoints.ts` (10 verticals / 64
endpoints) and `ops.ts`.

**3. New developer portal app (`frontend/portal/`)**
- App shell: `Header`, `Sidebar`, `AssistantPanel`, search modal,
notifications, tier switcher, theme toggle, MSW toggle.
- **Tier-aware** home (free / pay-as-you-go / enterprise): KPI strip,
30-day usage chart, onboarding checklist, quick actions, recent
activity, region health, product grid, and a curated **"Popular use
cases"** teaser.
- **Documents** view hosting the full, tab-filterable endpoint
catalogue.
- Placeholder views for Sources / Pipelines / Agents / Editor /
Infrastructure / Usage & Billing / Developer Docs / Settings (follow-up
phases).
- **MSW-mocked** API layer: `api/*` issues real `fetch`, intercepted by
mocks in dev/Storybook; pointing at a real backend is just a matter of
not registering MSW. `react-router` URLs; Tier / View / UI contexts.

**4. Tooling & guardrails**
- ESLint extended to `portal` + `shared`, with **layering-boundary
rules**: `shared/` may depend only on third-party packages and itself
(no `@app` / `@portal` / `@core` / `@proprietary` / Tauri), so it stays
cleanly extractable into a standalone package later.
- `dpdm` circular-dependency check now walks editor + portal + shared
(the old glob matched only 2 files).
- New **devDependencies only** — Storybook (+ a11y/docs/themes addons),
MSW. No runtime dependencies added.
- New tasks: `frontend:dev:portal`, `frontend:build:portal`.

## Testing done locally

- `tsc` for both `portal` and `shared` projects — clean
- `eslint --max-warnings=0` across the whole frontend — clean
- `dpdm` circular-dependency check — no cycles
- Editor builds clean: `vite build editor --mode core` (✓ built, only
the pre-existing >500 kB chunk-size advisory)
- Editor runs in dev (core mode) with **zero console errors**; portal
runs in dev across all three tiers

## Notes for reviewers

- The change is overwhelmingly **additive**: `shared/` and `portal/` are
brand-new; the existing editor is path-reference changes only.
- The portal is intentionally **mock-driven** at this stage — real
backends and the remaining views land in follow-up phases.

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have run `task check` to verify linters, typechecks, and tests
pass
- [x] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

---------

Co-authored-by: Claude Opus 4.8 (1M context) <[email protected]>

frontend/shared/components/Drawer.tsx

@@ -0,0 +1,171 @@
+import { useEffect, useId, useRef, type ReactNode } from "react";
+import { createPortal } from "react-dom";
+import "@shared/components/Drawer.css";
+
+const FOCUSABLE_SELECTOR =
+  'button:not([disabled]), [href], input:not([disabled]), select:not([disabled]), textarea:not([disabled]), [tabindex]:not([tabindex="-1"])';
+
+export type DrawerSide = "right" | "left";
+export type DrawerWidth = "sm" | "md" | "lg";
+
+export interface DrawerProps {
+  open: boolean;
+  onClose: () => void;
+  side?: DrawerSide;
+  /** Width preset. sm=22rem, md=27.5rem, lg=36rem. */
+  width?: DrawerWidth;
+  title?: ReactNode;
+  subtitle?: ReactNode;
+  /** Sticky footer slot below the body. */
+  footer?: ReactNode;
+  disableBackdropClose?: boolean;
+  disableEscapeClose?: boolean;
+  className?: string;
+  ariaLabel?: string;
+  children?: ReactNode;
+}
+
+/**
+ * Side drawer — sibling to {@link Modal}. Slides in from `side`, locks body
+ * scroll, closes on backdrop click or Escape. PipelineDetailDrawer, doc
+ * detail drawers, etc. should all sit on top of this primitive.
+ */
+export function Drawer({
+  open,
+  onClose,
+  side = "right",
+  width = "md",
+  title,
+  subtitle,
+  footer,
+  disableBackdropClose = false,
+  disableEscapeClose = false,
+  className,
+  ariaLabel,
+  children,
+}: DrawerProps) {
+  const dialogRef = useRef<HTMLElement | null>(null);
+  const titleId = useId();
+
+  useEffect(() => {
+    if (!open || disableEscapeClose) return;
+    function onKey(e: KeyboardEvent) {
+      if (e.key === "Escape") onClose();
+    }
+    document.addEventListener("keydown", onKey);
+    return () => document.removeEventListener("keydown", onKey);
+  }, [open, disableEscapeClose, onClose]);
+
+  useEffect(() => {
+    if (!open) return;
+    const previous = document.body.style.overflow;
+    document.body.style.overflow = "hidden";
+    return () => {
+      document.body.style.overflow = previous;
+    };
+  }, [open]);
+
+  useEffect(() => {
+    if (!open) return;
+    const previouslyFocused = document.activeElement as HTMLElement | null;
+    const dialog = dialogRef.current;
+    const first = dialog?.querySelector<HTMLElement>(FOCUSABLE_SELECTOR);
+    first?.focus();
+
+    function onKey(e: KeyboardEvent) {
+      if (e.key !== "Tab" || !dialog) return;
+      const focusables =
+        dialog.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR);
+      if (focusables.length === 0) {
+        e.preventDefault();
+        return;
+      }
+      const firstEl = focusables[0];
+      const lastEl = focusables[focusables.length - 1];
+      const active = document.activeElement;
+      if (e.shiftKey && active === firstEl) {
+        e.preventDefault();
+        lastEl.focus();
+      } else if (!e.shiftKey && active === lastEl) {
+        e.preventDefault();
+        firstEl.focus();
+      }
+    }
+
+    document.addEventListener("keydown", onKey);
+    return () => {
+      document.removeEventListener("keydown", onKey);
+      previouslyFocused?.focus?.();
+    };
+  }, [open]);
+
+  if (!open) return null;
+
+  function onBackdropClick() {
+    if (!disableBackdropClose) onClose();
+  }
+
+  const hasTitle = title !== undefined && title !== null;
+
+  return createPortal(
+    <>
+      <div
+        className="sui-drawer__backdrop"
+        onClick={onBackdropClick}
+        role="presentation"
+      />
+      <aside
+        ref={dialogRef}
+        className={[
+          "sui-drawer",
+          `sui-drawer--${side}`,
+          `sui-drawer--${width}`,
+          className ?? "",
+        ]
+          .filter(Boolean)
+          .join(" ")}
+        role="dialog"
+        aria-modal="true"
+        aria-labelledby={hasTitle ? titleId : undefined}
+        aria-label={!hasTitle ? ariaLabel : undefined}
+      >
+        {(title || subtitle) && (
+          <header className="sui-drawer__header">
+            <div className="sui-drawer__header-text">
+              {title && (
+                <div id={titleId} className="sui-drawer__title">
+                  {title}
+                </div>
+              )}
+              {subtitle && <div className="sui-drawer__sub">{subtitle}</div>}
+            </div>
+            <button
+              type="button"
+              className="sui-drawer__close"
+              onClick={onClose}
+              aria-label="Close"
+            >
+              <svg
+                viewBox="0 0 24 24"
+                width="16"
+                height="16"
+                fill="none"
+                stroke="currentColor"
+                strokeWidth={1.75}
+                strokeLinecap="round"
+                strokeLinejoin="round"
+                aria-hidden
+              >
+                <line x1="18" y1="6" x2="6" y2="18" />
+                <line x1="6" y1="6" x2="18" y2="18" />
+              </svg>
+            </button>
+          </header>
+        )}
+        <div className="sui-drawer__body">{children}</div>
+        {footer && <footer className="sui-drawer__footer">{footer}</footer>}
+      </aside>
+    </>,
+    document.body,
+  );
+}