* pubsub: consolidate into Spec, adopt Arc<SubscriptionId>, and wire through wallet/mint/WS/FFI
Refactor the pub/sub engine to a single Spec trait, move Event alongside it,
and propagate Arc-backed subscription IDs across the stack. This simplifies
generics, clarifies responsibilities, and preserves coalescing +
latest-on-subscribe semantics.
- **Single source of truth:** `Spec` owns `Topic`, `Event`, `SubscriptionId`,
`Context`, new_instance, and fetch_events.
- **Lean & explicit API:** Remove Topic trait split;
`Subscriber::send(Event)` carries sub-ID internally.
- **Performance/ergonomics:** `Arc<SubscriptionId>` avoids heavy clones and
makes channel/task hops trivial.
- Introduce `pub_sub/typ.rs` with:
- trait `Spec`
- trait `Event` colocated with Spec.
- Remove `pub_sub/event.rs` fold `Event` into `typ.rs`.
- Make `Pubsub<S>` generic over `Spec` and store `Arc<S>`.
- The subscriber holds `Arc<SubscriptionId>` and deduplicates the latest
entry per subscription.
- SubscriptionRequest: rename SubscriptionName → SubscriptionId; return
`Arc<...>` from `subscription_name()`.
- Remote consumer (Transport) now parameterized by `Spec`; control types
updated:
- `StreamCtrl<S>`, `SubscribeMessage<S>`, internal caches keyed by
`S::Topic`.
- Mint/wallet:
- Mint: `MintPubSubSpec` (Context = `DynMintDatabase`),
`PubSubManager(Pubsub<MintPubSubSpec>)`.
- Wallet: lightweight MintSubTopics Spec with `Context = ()`.
- IDs go Arc end-to-end:
- cdk-axum WS maps `HashMap<Arc<SubId>, JoinHandle<()>>`, publisher sends
`(Arc<SubId>, NotificationPayload)`.
- `subscription::{Params, WalletParams}` now use `Arc<...>`.
- cdk-ffi conversions & wallet glue updated.
- Integration tests updated for new types.
- Coalescing unchanged: multiple local subs to the same topic are combined
into a single remote sub.
- Backfill via `Spec::fetch_events(topics, Subscriber)`; Subscriber enforces
latest-only dedupe per subscription.
**Result:** a slimmer, more maintainable pub/sub core that’s easier to embed
across mint, wallet, transports, and FFI without sacrificing performance or
semantics.
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Co-authored-by: thesimplekid <tsk@thesimplekid.com>
