feat(oauth): add trips:share scope and redesign consent screen

Introduce trips:share as a dedicated OAuth scope for managing public
share links, decoupled from trips:read and trips:write. Share link
tools (get/create/delete_share_link) now gate on canShareTrips()
instead of the generic read/write scopes. Scope added to both client
and server definitions with full test coverage.

Redesign the consent screen from a narrow single-column card
(max-w-sm) to a two-panel layout (max-w-2xl): app identity and
action buttons on the left, scrollable scope list on the right.
Responsive — stacks vertically on mobile.

server/src/mcp/scopes.ts

@@ -6,6 +6,7 @@ export const SCOPES = {
   TRIPS_READ:          'trips:read',
   TRIPS_WRITE:         'trips:write',
   TRIPS_DELETE:        'trips:delete',
+  TRIPS_SHARE:         'trips:share',
   PLACES_READ:         'places:read',
   PLACES_WRITE:        'places:write',
   PACKING_READ:        'packing:read',
@@ -34,9 +35,10 @@ export interface ScopeInfo {
 }
 
 export const SCOPE_INFO: Record<Scope, ScopeInfo> = {
-  'trips:read':          { label: 'View trips & itineraries',   description: 'Read trips, days, day notes, members, and share links',                    group: 'Trips' },
+  'trips:read':          { label: 'View trips & itineraries',   description: 'Read trips, days, day notes, and members',                              group: 'Trips' },
   'trips:write':         { label: 'Edit trips & itineraries',   description: 'Create and update trips, days, notes, and manage members',                  group: 'Trips' },
   'trips:delete':        { label: 'Delete trips',               description: 'Permanently delete entire trips — this action is irreversible',              group: 'Trips' },
+  'trips:share':         { label: 'Manage share links',         description: 'Create, update, and revoke public share links for trips',                   group: 'Trips' },
   'places:read':         { label: 'View places & map data',     description: 'Read places, day assignments, tags, categories, and visited countries',      group: 'Places' },
   'places:write':        { label: 'Manage places',              description: 'Create, update, and delete places, assignments, tags, and atlas entries',    group: 'Places' },
   'packing:read':        { label: 'View packing lists',         description: 'Read packing items, bags, and category assignees',                          group: 'Packing' },
@@ -59,10 +61,10 @@ export const SCOPE_INFO: Record<Scope, ScopeInfo> = {
 // null scopes = static trek_ token = full access
 // ---------------------------------------------------------------------------
 
-/** trips:read OR trips:write OR trips:delete all grant read access to trips */
+/** trips:read OR trips:write OR trips:delete OR trips:share all grant read access to trips */
 export function canReadTrips(scopes: string[] | null): boolean {
   if (!scopes) return true;
-  return scopes.some(s => s === 'trips:read' || s === 'trips:write' || s === 'trips:delete');
+  return scopes.some(s => s === 'trips:read' || s === 'trips:write' || s === 'trips:delete' || s === 'trips:share');
 }
 
 /** group:write grants write access; for trips canReadTrips handles read */
@@ -83,6 +85,12 @@ export function canDeleteTrips(scopes: string[] | null): boolean {
   return scopes.includes('trips:delete');
 }
 
+/** trips:share is a separate scope for managing public share links */
+export function canShareTrips(scopes: string[] | null): boolean {
+  if (!scopes) return true;
+  return scopes.includes('trips:share');
+}
+
 export function validateScopes(requestedScopes: string[]): { valid: boolean; invalid: string[] } {
   const invalid = requestedScopes.filter(s => !ALL_SCOPES.includes(s as Scope));
   return { valid: invalid.length === 0, invalid };

server/src/mcp/tools/trips.ts

@@ -24,12 +24,13 @@ import {
   TOOL_ANNOTATIONS_DELETE, TOOL_ANNOTATIONS_NON_IDEMPOTENT,
   demoDenied, noAccess, ok,
 } from './_shared';
-import { canReadTrips, canWrite, canDeleteTrips } from '../scopes';
+import { canReadTrips, canWrite, canDeleteTrips, canShareTrips } from '../scopes';
 
 export function registerTripTools(server: McpServer, userId: number, scopes: string[] | null): void {
   const R = canReadTrips(scopes);
   const W = canWrite(scopes, 'trips');
   const D = canDeleteTrips(scopes);
+  const S = canShareTrips(scopes);
 
   // --- TRIPS ---
 
@@ -280,7 +281,7 @@ export function registerTripTools(server: McpServer, userId: number, scopes: str
     }
   );
 
-  if (R) server.registerTool(
+  if (S) server.registerTool(
     'get_share_link',
     {
       description: 'Get the current public share link for a trip, including its permission flags. Returns null if no share link exists.',
@@ -296,7 +297,7 @@ export function registerTripTools(server: McpServer, userId: number, scopes: str
     }
   );
 
-  if (W) server.registerTool(
+  if (S) server.registerTool(
     'create_share_link',
     {
       description: 'Create or update the public share link for a trip. Set permission flags to control what is visible to guests.',
@@ -324,7 +325,7 @@ export function registerTripTools(server: McpServer, userId: number, scopes: str
     }
   );
 
-  if (W) server.registerTool(
+  if (S) server.registerTool(
     'delete_share_link',
     {
       description: 'Revoke the public share link for a trip. Guests will no longer be able to access the shared view.',

server/tests/unit/mcp/scopes.test.ts

@@ -9,6 +9,7 @@ import {
   canWrite,
   canRead,
   canDeleteTrips,
+  canShareTrips,
   ALL_SCOPES,
   SCOPE_INFO,
 } from '../../../src/mcp/scopes';
@@ -22,6 +23,7 @@ describe('ALL_SCOPES', () => {
     expect(ALL_SCOPES).toContain('trips:read');
     expect(ALL_SCOPES).toContain('trips:write');
     expect(ALL_SCOPES).toContain('trips:delete');
+    expect(ALL_SCOPES).toContain('trips:share');
     expect(ALL_SCOPES).toContain('budget:read');
     expect(ALL_SCOPES).toContain('budget:write');
     expect(ALL_SCOPES).toContain('packing:read');
@@ -122,6 +124,10 @@ describe('canReadTrips', () => {
     expect(canReadTrips(['trips:delete'])).toBe(true);
   });
 
+  it('returns true when trips:share is present', () => {
+    expect(canReadTrips(['trips:share'])).toBe(true);
+  });
+
   it('returns false when only unrelated scopes are present', () => {
     expect(canReadTrips(['budget:read', 'packing:write'])).toBe(false);
   });
@@ -214,3 +220,37 @@ describe('canDeleteTrips', () => {
     expect(canDeleteTrips([])).toBe(false);
   });
 });
+
+// ---------------------------------------------------------------------------
+// canShareTrips
+// ---------------------------------------------------------------------------
+
+describe('canShareTrips', () => {
+  it('returns true when scopes is null (full access)', () => {
+    expect(canShareTrips(null)).toBe(true);
+  });
+
+  it('returns true when trips:share is present', () => {
+    expect(canShareTrips(['trips:share'])).toBe(true);
+  });
+
+  it('returns false when only trips:read is present', () => {
+    expect(canShareTrips(['trips:read'])).toBe(false);
+  });
+
+  it('returns false when only trips:write is present', () => {
+    expect(canShareTrips(['trips:write'])).toBe(false);
+  });
+
+  it('returns false when only trips:delete is present', () => {
+    expect(canShareTrips(['trips:delete'])).toBe(false);
+  });
+
+  it('returns false for unrelated scopes', () => {
+    expect(canShareTrips(['budget:write', 'packing:read'])).toBe(false);
+  });
+
+  it('returns false for empty scopes array', () => {
+    expect(canShareTrips([])).toBe(false);
+  });
+});