chore(api): remove User.prvkey field + thread-through helpers (Q1.2 Option b)

Atomic phase-1 final per design-questions Q1.2 Option (b) and the
2026-05-29T00:30Z architecture-decisions lock-in. Removing the
prvkey?: string field from the User interface flips the type system
into the pressure mechanism that forces phase-2 to start: every
remaining bucket-B sign-site (chat / forum / nostr-feed /
activities-bookmarks/RSVP / market / tasks) now fails vue-tsc until
it migrates to signEventViaLnbits() against POST /api/v1/auth/sign-event
(aiolabs/lnbits PR #29, deployed on aio-demo).

Changes:
- src/lib/api/lnbits.ts:
  - Drop `prvkey?: string` from User interface.
  - getCurrentUser(): /auth/nostr/me used to merge prvkey alongside
    pubkey; post-cascade the endpoint returns only the pubkey.
    Updated the comment + cleaned the merge object.
- src/modules/base/auth/auth-service.ts:
  - updateProfile() no longer threads `prvkey` through the merge.
    Server-side PATCH /auth publishes kind-0 via the signer per
    869f67c3; the webapp doesn't keep prvkey at all.
- src/modules/nostr-feed/components/NostrFeed.vue +
  src/modules/nostr-feed/components/ScheduledEventCard.vue:
  - Repoint the `ScheduledEvent` type import from the deleted
    `../services/ScheduledEventService` to
    `@/modules/tasks/services/TaskService`. Trivial post-#81-merge
    cleanup that fell through the dedup PR; same file exports the
    same interface.

vue-tsc --noEmit fails with 8 errors after this commit, all
TS2339 "Property 'prvkey' does not exist". The failing sites are
exactly the bucket-B targets the design doc enumerates as
phase-2 migration work:

| Failing site                                  | Bucket B kind |
|-----------------------------------------------|---------------|
| activities/composables/useBookmarks.ts:92,113 | kind 10003 (NIP-51 bookmarks) |
| activities/composables/useRSVP.ts:153,187     | kind 31925 (NIP-52 RSVP) |
| base/services/NostrTransportService.ts:100,112| kind 21000 (NIP-44 v2 RPC envelope) |
| market/composables/useMarket.ts:455           | NIP-44 gift-wrap (kind 1059) unwrap |
| nostr-feed/components/NostrFeed.vue:408       | kind 5 (deletion of own post) |

NOT caught by vue-tsc but still bucket-B (BaseService injection
pattern types `this.authService` as `any`, so optional chaining
bypasses the type check):

- chat/services/chat-service.ts:341,511,714
- forum/services/SubmissionService.ts:755,1167
- nostr-feed/services/SubmissionService.ts:769,1226
- nostr-feed/components/NoteComposer.vue:306
- nostr-feed/components/RideshareComposer.vue:423
- tasks/services/TaskService.ts:507,562,616

Those sites will runtime-fail (prvkey is undefined from the API
post-cascade) but won't surface at compile time. Phase 2's
per-module migration (Q5.2) catches them as each module flips.

The webapp WILL NOT BUILD CLEANLY after this PR merges to dev
until phase 2 lands. That's the intended trade-off per Q5.1 +
Q1.2; the broken-build interval is the design-intended pressure
mechanism to start phase 2. server-deploy's webapp-demo flake.lock
bump will fail until phase 2 lands; demo will stay on the
pre-PR-#84 webapp during that interval.

Refs:
- log:2026-05-29T00:30Z (consolidated decisions; Q1.2 Option (b)
  + Q5.1 risk: demo gap acceptable)
- log:2026-05-29T17:30Z (lnbits confirming this PR stays
  atomic-after-the-two-bucket-A PRs)
- ~/dev/coordination/webapp-design-questions.md Q1.2 + Q5.1
- Parent initiative: aiolabs/lnbits#9 (signer abstraction / bunker)
- Sibling PRs (stacked base→head): #82 → #83 → this

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/modules/activities/composables/useActivityDetail.ts

@@ -32,24 +32,18 @@ export function useActivityDetail(activityId: string) {
       isLoading.value = true
       error.value = null
 
-      // Scope both the subscription and the one-shot query to this
+      // Subscribe and wait for this specific event
-      // activity's d-tag. Without this scope, the query asks every
-      // relay for every kind-31922/31923 event and races a 5s timeout
-      // to find ours — on a cold page refresh that race is often lost
-      // even when the activity is reachable.
-      const detailFilters = { dTags: [activityId] }
-
       unsubscribe = nostrService.subscribeToCalendarEvents(
         (incoming) => {
           store.upsertActivity(incoming)
           if (incoming.id === activityId) {
             isLoading.value = false
           }
-        },
+        }
-        detailFilters
       )
 
-      const results = await nostrService.queryCalendarEvents(detailFilters)
+      // Also do a one-shot query
+      const results = await nostrService.queryCalendarEvents()
       store.upsertActivities(results)
 
       // If we still don't have it after query, stop loading

src/modules/activities/services/ActivitiesNostrService.ts

@@ -23,8 +23,6 @@ export interface CalendarEventFilters {
   hashtags?: string[]
   /** Filter by geohash prefix (NIP-52 'g' tag) */
   geohash?: string
-  /** Filter by NIP-52 'd' tag — scopes the query to specific parameterized-replaceable events */
-  dTags?: string[]
 }
 
 /**
@@ -150,7 +148,6 @@ export class ActivitiesNostrService extends BaseService {
     if (filters?.authors?.length) filter.authors = filters.authors
     if (filters?.hashtags?.length) filter['#t'] = filters.hashtags
     if (filters?.geohash) filter['#g'] = [filters.geohash]
-    if (filters?.dTags?.length) filter['#d'] = filters.dTags
 
     return [filter]
   }