## Goal
Make `projection` and `aggregate` compatible to run behind the same gateway and against the same NATS JetStream cluster, with consistent shared types and operational conventions.

## Constraints
- Keep both services independently deployable.
- Preserve existing stream/subject conventions unless they are unsafe for multi-instance use.
- Prefer backward-compatible changes in message formats (optional fields, tolerant decoding).
- Keep changes minimal and verified by fmt/test/clippy.

## Compatibility Checklist
### JetStream / NATS
- Stream name: `AGGREGATE_EVENTS` in both services.
- Subject pattern: `tenant.*.aggregate.*.*` in both services.
- Consumer durability:
  - Projection: stable durable name (or per-view derived durable).
  - Aggregate: avoid fixed durable names for ad-hoc fetch operations to prevent collisions across instances.

### Common Types
- `TenantId`: identical newtype behavior across both codebases.
- Event payload shape:
  - Aggregate publishes `types::Event` with `event_id`, `command_id`, `version`, etc.
  - Projection consumes an `EventEnvelope`; keep required fields stable and add optional fields to mirror aggregate where useful.

## Plan (Implementation Order)
1. Align projection’s event envelope schema to accept and (optionally) emit aggregate-compatible identifiers:
   - Add optional `event_id`, `command_id`, `version` fields.
   - Keep decoding tolerant with `#[serde(default)]`.
   - Avoid changing serialized output unless those fields are present.
2. Make aggregate’s JetStream fetch consumer safe for shared clusters:
   - Generate unique consumer names per fetch call (tenant + aggregate + uuid).
   - Use explicit ack policy.
   - Bound fetch loops by timeout/idle to avoid hanging.
   - Best-effort delete the consumer when done.
3. Enforce consistent “strict clippy” hygiene:
   - Remove trivial `assert!(true)` and other clippy warnings in aggregate so both crates can run `cargo clippy -- -D warnings`.
4. Verification:
   - `cargo fmt --check`
   - `cargo test`
   - `cargo clippy --all-targets -- -D warnings`

## Expected Outcomes
- Both binaries can connect to the same JetStream cluster without consumer name collisions.
- Projection can decode aggregate-published events and has access to event identifiers/versions when present.
- Both repositories share the same strictness level for formatting and linting.