chore: scaffold moments workspace

Cargo workspace with five crates per architecture conventions:

- moments-entities: Source enum, Event, EventQuery, SourceSummary
- moments-core:     EventReader / EventWriter ports
- moments-data:     PgStore (sqlx postgres adapter) + 0001_init.sql
- moments-api:      axum binary; /v1/{healthz,events,sources}
- moments-worker:   skeleton; pollers land in step 2

Sources committed-to for ingestion: github, gitea, hg, bugzilla.
Workstation events explicitly retired (not deferred).

Build + clippy clean. sqlx queries use the runtime API for now;
will switch to compile-time-checked macros + .sqlx offline cache
once magrathea has the moments_{ro,rw} roles and database created.

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

crates/moments-worker/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "moments-worker"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+authors.workspace = true
+
+[dependencies]
+moments-entities.workspace = true
+moments-core.workspace = true
+moments-data.workspace = true
+tokio.workspace = true
+tracing.workspace = true
+tracing-subscriber.workspace = true
+anyhow.workspace = true
+clap.workspace = true
+reqwest.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+chrono.workspace = true