refactor(peer-support): delete provably dead code (Phase 1)

The Skills Exchange + Peer Support feature was replaced by Community
Connections on 2026-04-05, but several files and code paths were left
in place as backward-compat. None are reachable from the live UI:

- usePeerSupport.js composable: not imported anywhere
- PeerSupportBadge.vue: not imported anywhere
- peer-support.vue: stub redirect with no incoming links
- /api/peer-support.get.js: only consumed by usePeerSupport
- /api/members/me/peer-support.patch.js: same
- profile.patch.js offering/lookingFor write branches: profile form
  no longer sends these fields (only writes communityConnections.*)
- PEER_SUPPORT_ENABLED/DISABLED activity types and renderers: only
  written by the deleted peer-support.patch endpoint. The activityText
  formatter has a fallback for unknown types so existing records
  still display ("peer support enabled" with a generic icon).

Tests updated to drop peerSupportUpdateSchema coverage and the
offering/lookingFor passthrough assertion.

schemas.js cleanup deferred — concurrent communityConnections →
communityEcology rename is in flight in the working tree.

tests/server/api/members-profile-patch.test.js

@@ -27,8 +27,6 @@ describe('members profile PATCH endpoint', () => {
     bio: 'Updated bio',
     location: 'NYC',
     socialLinks: { twitter: '@test' },
-    offering: { text: 'help', tags: ['code'] },
-    lookingFor: { text: 'feedback', tags: ['design'] },
     showInDirectory: true
   }
 
@@ -137,21 +135,5 @@ describe('members profile PATCH endpoint', () => {
       expect(setData).toHaveProperty('socialLinks')
     })
 
-    it('passes offering and lookingFor nested objects through', async () => {
-      const event = createMockEvent({
-        method: 'PATCH',
-        path: '/api/members/profile',
-        body: {
-          offering: { text: 'mentoring', tags: ['code', 'design'] },
-          lookingFor: { text: 'feedback', tags: ['art'] }
-        }
-      })
-
-      await profilePatchHandler(event)
-
-      const setData = Member.findByIdAndUpdate.mock.calls[0][1].$set
-      expect(setData.offering).toEqual({ text: 'mentoring', tags: ['code', 'design'] })
-      expect(setData.lookingFor).toEqual({ text: 'feedback', tags: ['art'] })
-    })
   })
 })