feat: add route-level role guard to prevent wrong-role page access

[johneliud]

Problem

A freelancer can navigate directly to /client/projects/new or /client/listings/new and the page renders normally. There is no middleware or component-level guard redirecting based on role. The contract will correctly reject unauthorized transactions, but the UX is confusing — a freelancer sees a form, fills it out, and only fails at the signing step.

Proposed Solution

Since wallet address = identity (no fixed role per wallet), the guard should be contextual rather than hard:

Short-term (recommended for demo):

• Add a URL-based notice: if a wallet has no client listings/projects, the client dashboard nudges them to create one. If no projects as freelancer, nudge to browse listings. No hard block.

Medium-term:

• Add a useRouteGuard hook that checks wallet connectivity before rendering action pages
• Pages like /client/listings/new should redirect to wallet connect screen if !isConnected (currently shows a wallet prompt inline — redirect is cleaner)

Long-term:

• Allow users to declare a primary role on first connect (stored off-chain in Supabase) and use that to personalize navigation

Acceptance Criteria

• Disconnected users are redirected to a connect prompt instead of seeing inline forms
• Client-only pages display an "unauthorized" state if the connected wallet has no client activity (soft guard, not hard block)

Priority

Low — not a correctness issue (contract enforces auth), but degrades UX.

[johneliud]

Implemented components/WalletGuard.tsx — a shared component that renders a full connect prompt (with Freighter install fallback) when wallet is not connected, replacing the scattered per-page inline prompts.

Applied to:

• /client dashboard
• /freelancer dashboard
• /client/listings/new
• /client/projects/new

Pages like /client/projects/[id], /freelancer/projects/[id], and /projects/[id] deliberately keep inline wallet prompts since they can partially render without a connected wallet (project data is public).