Phase 2: analytics rollups, geo breakdown, event feed (backend)

- Idempotent hourly rollup (run_rollup, INSERT ... ON CONFLICT DO UPDATE into
  analytics_rollups_hourly) + Tokio background task (startup then hourly)
- GET /v1/cards/{id}/analytics/geo — country-grouped visit counts
- GeoResolver trait: real MaxMind under the `geoip` feature, no-op default;
  raw IP resolved then discarded (only hash + coarse country/city persisted)
- analytics_events now store country/city; rollups read query for the dashboard

2 new tests (geo grouping, rollup aggregation + idempotency); 75 backend tests.
fmt + clippy clean; geoip feature compiles.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

cardclaws-backend/crates/cardclaws-api/Cargo.toml

@@ -14,6 +14,7 @@ workspace = true
 # structurally-correct but unsigned passes — logged loudly at startup.
 default = []
 apple-signing = ["cardclaws-wallet/apple-signing"]
+geoip = ["dep:maxminddb"]
 
 [[bin]]
 name = "cardclaws-api"
@@ -43,6 +44,7 @@ rand = { workspace = true }
 base64 = { workspace = true }
 validator = { workspace = true }
 async-trait = { workspace = true }
+maxminddb = { version = "0.24", optional = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
 thiserror = { workspace = true }
@@ -51,6 +53,7 @@ thiserror = { workspace = true }
 cardclaws-auth = { workspace = true }
 cardclaws-wallet = { workspace = true }
 cardclaws-config = { workspace = true }
+cardclaws-db = { workspace = true }
 tower = { workspace = true, features = ["util"] }
 http-body-util = "0.1"
 tokio = { workspace = true }