feat(branding): introduce support for icon-only branding and better flexibility

[govindavashishtha]

Summary

• Add theme.brand.mode so hosts pick chrome look first: icon-title | icon-only | logo (omit brand for default TrueForge marks).
• BrandConfig is a discriminated union on mode. name is required and always labels the mark (alt / aria-label); visible title text only for icon-title.
• Compact surfaces always use the square icon. Expanded chrome uses logo when mode: 'logo', otherwise icon (+ title when icon-title).
• resolveBrandChrome() maps mode → { expandedVariant, collapsedVariant, showTitle }; SidebarLayout uses it instead of field heuristics.
• Docs, changelog, and tests updated for the new contract.

Contract

brand.mode	Required	Expanded	Collapsed
omit brand	—	TF wordmark	TF square
'icon-title'	name (+ optional icon)	square + title	square
'icon-only'	name, icon	square (alt only)	square
'logo'	name, icon, logo	wide logo (alt only)	square

Usage

// Default TrueForge wordmark / square mark
<TrueForgeUI server={server} layout="sidebar" />

// Icon + title
theme={{ brand: { mode: 'icon-title', name: 'Acme', icon: '/icon.svg' } }}

// Icon only (name kept for alt)
theme={{ brand: { mode: 'icon-only', name: 'Acme', icon: '/icon.svg' } }}

// Wide logo when expanded
theme={{
  brand: {
    mode: 'logo',
    name: 'Acme',
    icon: '/icon.svg',
    logo: '/wordmark.svg',
    href: '/',
  },
}}

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Breaking change to `theme.brand` shape affects all customized branding; behavior is localized to theme/layout chrome, not auth or data paths.
> 
> **Overview**
> Introduces **`theme.brand.mode`** (`icon-title` | `icon-only` | `logo`) so hosts choose header chrome up front. **`BrandConfig`** is now a discriminated union: square **`icon`**, optional wide **`logo`**, required **`name`** (always for a11y; visible title text only for `icon-title`). **`href`** moves to the brand object (off per-image config).
> 
> **`BrandLogo`** gains **`variant="icon" | "logo"`**; when `brand` is omitted, expanded surfaces show a built-in TrueForge **wordmark** SVG and compact surfaces keep the square mark. **`resolveBrandChrome()`** is exported and **`SidebarLayout`** uses it for expanded/collapsed variants and title visibility (widget FAB / welcome use `variant="icon"`).
> 
> Docs, README, changelog, and tests reflect the new contract. **Migration:** replace `brand: { name, logo }` with the appropriate `mode` plus `icon` / `logo` fields.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit 3ed36defb76ac9ca322aa8d2703f5b70a901505c. Bugbot is set up for automated code reviews on this repo. Configure [here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

[changeset-bot]

🦋 Changeset detected

Latest commit: 3ed36de

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@truefoundry/trueforge-ui	Minor
@truefoundry/trueforge	Patch
frontend	Patch

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Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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[vinit-truefoundry]

can we extract this out in a separate constant and reuse it ?
As the same class is being used above