InlineElicitationRequest: support URL variant via discriminated union (blocked on hook layer)

[cliffhall]

Background

Documented as a Phase 5 audit partial in specification/v2_ux_interfaces.md (PR #1236). InlineElicitationRequest currently accepts only the form-mode variant: request: ElicitRequest['params']. The spec target is a discriminated union: request: ElicitRequest | InspectorUrlElicitRequest.

Blocked on the v2 core hook layer effort for the same reason as the companion ElicitationUrlPanel issue: InspectorUrlElicitRequest doesn't exist in core/mcp/types.ts yet.

Acceptance criteria

• After InspectorUrlElicitRequest lands in core/mcp/types.ts, InlineElicitationRequestProps is updated: request: ElicitRequest['params'] | InspectorUrlElicitRequest.
• Internal rendering discriminates on the request shape (presence of url field, or whatever discriminator the wrapper carries) — not on a separate mode prop.
• The mode prop, if present, is removed.
• Form-variant rendering is unchanged from today.
• URL-variant rendering matches ElicitationUrlPanel's compact equivalent: message + URL display + copy/open/cancel buttons in a smaller card layout.
• Stories cover: (a) form variant (existing), (b) URL variant, (c) URL variant with isWaiting=true.

Test plan

• npm run format && npm run lint && npm run build clean.
• Existing form-variant stories render visually unchanged.
• New URL-variant stories show the compact URL card; action logger fires onCopyUrl / onOpenInBrowser / onCancel.
• No leftover mode prop in git grep -n 'InlineElicitationRequest' output.

Out of scope

• Reconciling the form-variant request typing with the full ElicitRequest (the spec target says ElicitRequest | InspectorUrlElicitRequest, but using ElicitRequest['params'] for the form half is acceptable per the same logic that satisfies ElicitationFormPanel).
• Building the pending-elicitation queue itself.

Blocked by

• v2 core/ hook layer effort — provides InspectorUrlElicitRequest.
• Companion: ElicitationUrlPanel wrapper adoption issue (parallel work, same blocker).

Related

• Spec entry: specification/v2_ux_interfaces.md § InlineElicitationRequest
• Companion: specification/v2_ux_interfaces.md § ElicitationUrlPanel
• Audit: PR Phase 5 audit: annotate spec, close HistoryControls partial #1236