feat: implement dashboard ban overview (Stage 5)

- Add ban_service reading fail2ban SQLite DB via read-only aiosqlite
- Add geo_service resolving IPs via ip-api.com with 10k in-memory cache
- Add GET /api/dashboard/bans and GET /api/dashboard/accesses endpoints
- Add TimeRange, DashboardBanItem, DashboardBanListResponse, AccessListItem,
  AccessListResponse models in models/ban.py
- Build BanTable component (Fluent UI DataGrid) with bans/accesses modes,
  pagination, loading/error/empty states, and ban-count badges
- Build useBans hook managing time-range and pagination state
- Update DashboardPage: status bar + time-range toolbar + tab switcher
- Add 37 new backend tests (ban service, geo service, dashboard router)
- All 141 tests pass; ruff/mypy --strict/tsc --noEmit clean

backend/app/models/ban.py

@@ -3,8 +3,25 @@
 Request, response, and domain models used by the ban router and service.
 """
 
+from typing import Literal
+
 from pydantic import BaseModel, ConfigDict, Field
 
+# ---------------------------------------------------------------------------
+# Time-range selector
+# ---------------------------------------------------------------------------
+
+#: The four supported time-range presets for the dashboard views.
+TimeRange = Literal["24h", "7d", "30d", "365d"]
+
+#: Number of seconds represented by each preset.
+TIME_RANGE_SECONDS: dict[str, int] = {
+    "24h": 24 * 3600,
+    "7d": 7 * 24 * 3600,
+    "30d": 30 * 24 * 3600,
+    "365d": 365 * 24 * 3600,
+}
+
 
 class BanRequest(BaseModel):
     """Payload for ``POST /api/bans`` (ban an IP)."""
@@ -89,3 +106,87 @@ class ActiveBanListResponse(BaseModel):
 
     bans: list[ActiveBan] = Field(default_factory=list)
     total: int = Field(..., ge=0)
+
+
+# ---------------------------------------------------------------------------
+# Dashboard ban-list / access-list view models
+# ---------------------------------------------------------------------------
+
+
+class DashboardBanItem(BaseModel):
+    """A single row in the dashboard ban-list table.
+
+    Populated from the fail2ban database and enriched with geo data.
+    """
+
+    model_config = ConfigDict(strict=True)
+
+    ip: str = Field(..., description="Banned IP address.")
+    jail: str = Field(..., description="Jail that issued the ban.")
+    banned_at: str = Field(..., description="ISO 8601 UTC timestamp of the ban.")
+    service: str | None = Field(
+        default=None,
+        description="First matched log line — used as context for the ban.",
+    )
+    country_code: str | None = Field(
+        default=None,
+        description="ISO 3166-1 alpha-2 country code, or ``null`` if unknown.",
+    )
+    country_name: str | None = Field(
+        default=None,
+        description="Human-readable country name, or ``null`` if unknown.",
+    )
+    asn: str | None = Field(
+        default=None,
+        description="Autonomous System Number string (e.g. ``'AS3320'``).",
+    )
+    org: str | None = Field(
+        default=None,
+        description="Organisation name associated with the IP.",
+    )
+    ban_count: int = Field(..., ge=1, description="How many times this IP was banned.")
+
+
+class DashboardBanListResponse(BaseModel):
+    """Paginated dashboard ban-list response."""
+
+    model_config = ConfigDict(strict=True)
+
+    items: list[DashboardBanItem] = Field(default_factory=list)
+    total: int = Field(..., ge=0, description="Total bans in the selected time window.")
+    page: int = Field(..., ge=1)
+    page_size: int = Field(..., ge=1)
+
+
+class AccessListItem(BaseModel):
+    """A single row in the dashboard access-list table.
+
+    Each row represents one matched log line (failure) that contributed to a
+    ban — essentially the individual access events that led to bans within the
+    selected time window.
+    """
+
+    model_config = ConfigDict(strict=True)
+
+    ip: str = Field(..., description="IP address of the access event.")
+    jail: str = Field(..., description="Jail that recorded the access.")
+    timestamp: str = Field(
+        ...,
+        description="ISO 8601 UTC timestamp of the ban that captured this access.",
+    )
+    line: str = Field(..., description="Raw matched log line.")
+    country_code: str | None = Field(default=None)
+    country_name: str | None = Field(default=None)
+    asn: str | None = Field(default=None)
+    org: str | None = Field(default=None)
+
+
+class AccessListResponse(BaseModel):
+    """Paginated dashboard access-list response."""
+
+    model_config = ConfigDict(strict=True)
+
+    items: list[AccessListItem] = Field(default_factory=list)
+    total: int = Field(..., ge=0)
+    page: int = Field(..., ge=1)
+    page_size: int = Field(..., ge=1)