add Nostr publishing and bidirectional sync

- nostr/ vendors NostrEvent + the nostrclient WebSocket bridge from
  the events extension, retagged [TASKS] / subscription-id "tasks-*".
- nostr_publisher builds kind 31922 with the `event-type: task` tag
  (per aiolabs/webapp#25 — disambiguates from kind-31922 activities on
  shared relays), kind 31925 with task-status / occurrence /
  completed_at, and kind 5 deletions for both.
- nostr_hooks bridges task/completion mutations to the publisher and
  persists the resulting nostr_event_id back onto the local row.
- nostr_sync subscribes to {31922, 31925, 5/#k} and filters 31922
  client-side on `event-type: task` because most relays don't index
  custom single-letter tags.

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

nostr_hooks.py

@@ -0,0 +1,97 @@
+"""Helpers that bridge task-mutation handlers to the Nostr publisher.
+
+Sits between views_api and nostr_publisher so we don't pull the publisher
+through the views module (which would create an import cycle via models)."""
+
+from loguru import logger
+
+from .crud import update_task
+from .models import Task, TaskCompletion
+from .nostr_publisher import (
+    publish_completion_delete_to_nostr,
+    publish_completion_to_nostr,
+    publish_task_to_nostr,
+)
+
+
+async def _account_keys(wallet_id: str) -> tuple[str, str] | None:
+    """Fetch (pubkey, prvkey) for the wallet's owning account. Returns None
+    when the account is missing keys, so callers can skip cleanly."""
+    from lnbits.core.crud.users import get_account
+    from lnbits.core.crud.wallets import get_wallet
+
+    wallet_obj = await get_wallet(wallet_id)
+    if not wallet_obj:
+        return None
+    account = await get_account(wallet_obj.user)
+    if not account or not account.pubkey or not account.prvkey:  # type: ignore[attr-defined]
+        return None
+    return account.pubkey, account.prvkey  # type: ignore[attr-defined]
+
+
+async def publish_or_delete_task_event(
+    task: Task, *, delete: bool = False
+) -> None:
+    """Publish (or delete-publish) the NIP-52 kind 31922 for `task`.
+
+    Errors are logged and swallowed so a Nostr outage doesn't break the
+    HTTP flow that triggered the publish."""
+    try:
+        from . import nostr_client
+
+        keys = await _account_keys(task.wallet)
+        if not keys:
+            return
+        pubkey, prvkey = keys
+
+        nostr_event = await publish_task_to_nostr(
+            nostr_client, task, pubkey, prvkey, delete=delete
+        )
+        if nostr_event and not delete:
+            task.nostr_event_id = nostr_event.id
+            task.nostr_event_created_at = nostr_event.created_at
+            await update_task(task)
+    except Exception as exc:
+        logger.warning(f"[TASKS] Nostr task publish failed: {exc}")
+
+
+async def publish_task_completion(
+    task: Task, completion: TaskCompletion
+) -> str | None:
+    """Publish a kind 31925 completion. Returns the Nostr event id so the
+    caller can persist it as the completion's primary key, replacing the
+    locally-generated hash from the optimistic insert."""
+    try:
+        from . import nostr_client
+
+        keys = await _account_keys(task.wallet)
+        if not keys:
+            return None
+        pubkey, prvkey = keys
+
+        nostr_event = await publish_completion_to_nostr(
+            nostr_client, task.address, completion, pubkey, prvkey
+        )
+        return nostr_event.id if nostr_event else None
+    except Exception as exc:
+        logger.warning(f"[TASKS] Nostr completion publish failed: {exc}")
+        return None
+
+
+async def publish_completion_delete(
+    wallet_id: str, completion_id: str
+) -> None:
+    """Publish a NIP-09 delete for a previously-published completion."""
+    try:
+        from . import nostr_client
+
+        keys = await _account_keys(wallet_id)
+        if not keys:
+            return
+        pubkey, prvkey = keys
+
+        await publish_completion_delete_to_nostr(
+            nostr_client, completion_id, pubkey, prvkey
+        )
+    except Exception as exc:
+        logger.warning(f"[TASKS] Nostr completion delete failed: {exc}")