Add Dashboards UI: PromQL-backed bar/line/pie panels saved per profile (ticket 014)

Backend: replace Profile.dashboards' opaque JSON stub with typed
Dashboard/Panel structs, add ProfileStore CRUD (create/save/list/delete
dashboard) and matching /api/settings/profiles/:name/dashboards[/:id] routes,
with tests covering the HTTP round trip and persistence across a simulated
restart.

Frontend: add recharts (lightweight, React 19-compatible) and a Dashboards
component with a dashboard builder (create dashboards, add/remove/edit panels
with a PromQL query + chart type), live per-panel previews that respect the
active time range and show malformed-query errors inline instead of crashing,
and load/save wired to the new profile-backed persistence.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

src/dto.rs

@@ -1,6 +1,6 @@
 use crate::data_value::{MetricPrimitiveKind, RegexToMetricPrimitiveMatcher};
 use crate::metric_primitive::MetricPrimitive;
-use crate::profile::Profile;
+use crate::profile::{ChartType, Dashboard, Panel, Profile};
 use crate::settings::{ColorScheme, CssEntry, Settings};
 use serde::{Deserialize, Serialize};
 use std::collections::BTreeMap;
@@ -241,3 +241,84 @@ impl From<&Profile> for ProfileSummaryDto {
 pub struct CreateProfileRequest {
     pub name: String,
 }
+
+/// One panel within a dashboard (ticket 014): a PromQL query plus how to
+/// chart its result. Mirrors `profile::Panel`.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PanelDto {
+    pub id: String,
+    pub title: String,
+    pub promql: String,
+    pub chart_type: ChartType,
+}
+
+impl From<&Panel> for PanelDto {
+    fn from(panel: &Panel) -> Self {
+        PanelDto {
+            id: panel.id.clone(),
+            title: panel.title.clone(),
+            promql: panel.promql.clone(),
+            chart_type: panel.chart_type,
+        }
+    }
+}
+
+impl From<&PanelDto> for Panel {
+    fn from(dto: &PanelDto) -> Self {
+        Panel {
+            id: dto.id.clone(),
+            title: dto.title.clone(),
+            promql: dto.promql.clone(),
+            chart_type: dto.chart_type,
+        }
+    }
+}
+
+/// A saved dashboard (ticket 014), as returned by
+/// `GET /api/settings/profiles/:name/dashboards` and friends. Mirrors
+/// `profile::Dashboard`.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct DashboardDto {
+    pub id: String,
+    pub name: String,
+    pub panels: Vec<PanelDto>,
+}
+
+impl From<&Dashboard> for DashboardDto {
+    fn from(dashboard: &Dashboard) -> Self {
+        DashboardDto {
+            id: dashboard.id.clone(),
+            name: dashboard.name.clone(),
+            panels: dashboard.panels.iter().map(PanelDto::from).collect(),
+        }
+    }
+}
+
+impl From<&DashboardDto> for Dashboard {
+    fn from(dto: &DashboardDto) -> Self {
+        Dashboard {
+            id: dto.id.clone(),
+            name: dto.name.clone(),
+            panels: dto.panels.iter().map(Panel::from).collect(),
+        }
+    }
+}
+
+/// Request body for `POST /api/settings/profiles/:name/dashboards`: creates
+/// a new, empty dashboard with this name (see `ProfileStore::create_dashboard`).
+#[derive(Debug, Deserialize)]
+pub struct CreateDashboardRequest {
+    pub name: String,
+}
+
+/// Request body for
+/// `PUT /api/settings/profiles/:name/dashboards/:dashboard_id`: replaces the
+/// dashboard's `name`/`panels` (see `ProfileStore::save_dashboard`). The
+/// dashboard `id` in the URL is authoritative — any `id` in the body is
+/// ignored.
+#[derive(Debug, Deserialize)]
+pub struct SaveDashboardRequest {
+    pub name: String,
+    #[serde(default)]
+    pub panels: Vec<PanelDto>,
+}