Fix HIGH priority issues: unbounded queries, rate limiting, health checks

Issue #3 - Unbounded Query Results (OOM):
- get_all_archived_history() now uses keyset pagination with bounded max_rows (50k default)
- Added 'id' field to records from get_archived_history() and get_archived_history_keyset()
- Protocol signature updated with page_size, max_rows, last_ban_id params

Issue #7 - Docker Health Check Fails:
- Added curl to Dockerfile.backend runtime image
- HEALTHCHECK now uses 'curl -f http://localhost:8000/api/health'
- compose.prod.yml: increased start_period to 40s, timeout to 10s
- Frontend healthcheck proxies to backend /api/health

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/app/models/history_domain.py

@@ -0,0 +1,64 @@
+"""History domain models.
+
+Internal domain-focused models used by history_service. These represent the
+business domain layer and are independent of HTTP response shapes.
+
+Response models are defined in `app.models.history` and mappers convert domain
+models to response models at the router boundary.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class DomainHistoryBanItem:
+    """A single row in the history ban-list table (domain model)."""
+
+    ip: str
+    jail: str
+    banned_at: str
+    ban_count: int
+    failures: int = 0
+    matches: list[str] | None = None
+    country_code: str | None = None
+    country_name: str | None = None
+    asn: str | None = None
+    org: str | None = None
+
+
+@dataclass(frozen=True)
+class DomainHistoryList:
+    """Paginated history ban-list (domain model)."""
+
+    items: list[DomainHistoryBanItem]
+    total: int
+    page: int
+    page_size: int
+
+
+@dataclass(frozen=True)
+class DomainIpTimelineEvent:
+    """A single ban event in a per-IP timeline (domain model)."""
+
+    jail: str
+    banned_at: str
+    ban_count: int
+    failures: int = 0
+    matches: list[str] | None = None
+
+
+@dataclass(frozen=True)
+class DomainIpDetail:
+    """Full historical record for a single IP address (domain model)."""
+
+    ip: str
+    total_bans: int
+    total_failures: int
+    last_ban_at: str | None = None
+    country_code: str | None = None
+    country_name: str | None = None
+    asn: str | None = None
+    org: str | None = None
+    timeline: list[DomainIpTimelineEvent] | None = None