mecatui: evaluate bounded /connect target picker #2176

Scope

Evaluate the saved-target picker in cmd/mecatui/ui/connect.go for bounded list adoption. renderConnectOverlay wraps each target's label and issuer/client/audience metadata, then renders every target without a height budget; a long saved-target inventory can extend past the conversation region with the selected target off-screen. The OIDC sign-in row is also selectable. This is a picker UI change, not an auth or connection-policy change.

Required outcome

• Decide whether bounded.List can represent each target as one logical, possibly multiline item, plus the sign-in row. If justified, budget error/auth hints, title, footer and confirmation chrome; reveal the selection, use stable target IDs and standard presentListRow treatment when appropriate, and provide safe compact behavior. Explicitly retain the current implementation if migration does not improve correctness or behavior.
• Preserve failed-target/rejected-auth restrictions, target ordering, selected action, loading/error/empty states, confirmation flow, live hints, metadata sanitization, and connection/restart intent. Do not touch token or credential handling.

Verification

Scenario-first tests for many wrapped targets, short/resize geometry, selected target + sign-in row reachability, error/auth-hint heights, selection identity after refresh, and the correct connect/confirm action. Run focused connect/UI and bounded tests.

Relates to #1742 and #1589. Click-to-select is separately tracked in #769.