feat(camera): add camera management functionality and data flow documentation

- Implemented camera slice in Redux store for managing camera state.
- Added new tables in PostgreSQL for camera devices, lending, and audit logs.
- Created camera-related schemas in contracts for validation.
- Developed camera data flow documentation outlining ingest and read processes.
- Introduced async thunks for fetching, creating, lending, returning, and updating cameras.

docs/camera-data-flow.md

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+# Camera Data Flow
+
+This document describes the current camera ingest and read flow.
+
+## Overview
+
+- Active cameras auto-generate ingest events every 1 second.
+- Events are enqueued to Redis Stream `telemetry:stream`.
+- A Redis Stream worker consumes events, retries failed writes up to 3 times, and dead-letters failures.
+- Worker writes:
+  - Mongo raw telemetry events
+  - Redis presence key with TTL
+  - Postgres latest current state on every event
+  - Postgres analytics snapshot at most once every 5 seconds per device
+- UI reads camera status by polling every 1 second.
+
+## System Flow Diagram
+
+```mermaid
+flowchart LR
+  subgraph CameraLane[Camera Lane]
+    C1[Active Cameras]
+    T1[Auto Simulator in ingest-api\nEvery 1 second]
+    C1 --> T1
+  end
+
+  subgraph IngestAPI[ingest-api Koa]
+    E1[Build telemetry event]
+    Q1[XADD telemetry:stream]
+    API[POST /telemetry]
+    E1 --> Q1
+    API --> Q1
+  end
+
+  T1 --> E1
+
+  subgraph Redis[Redis]
+    S1[(Stream: telemetry:stream)]
+    G1[Consumer Group Worker\nRetries up to 3]
+    DLQ[(Stream: telemetry:stream:dlq)]
+    P1[(Presence key device:id TTL)]
+  end
+
+  Q1 --> S1
+  S1 --> G1
+  G1 -->|on repeated failure| DLQ
+
+  subgraph Stores[Storage Writes by Worker]
+    M1[(Mongo telemetry raw events)]
+    PG1[(Postgres device_current_state\nLatest status)]
+    PG2[(Postgres device_status_snapshots\nAt most once per 5 sec per device)]
+  end
+
+  G1 --> M1
+  G1 --> P1
+  G1 --> PG1
+  G1 --> PG2
+
+  subgraph ReadPath[Read Path]
+    UI[Web /devices]
+    CAMAPI[GET /cameras\nGET /cameras/:id/latest]
+    UI -->|poll every 1 second| CAMAPI
+    CAMAPI --> PG1
+    CAMAPI --> P1
+  end
+```
+
+## Event Timeline Diagram
+
+```mermaid
+sequenceDiagram
+  participant Cam as Camera Simulator
+  participant Ingest as ingest api
+  participant Stream as Redis Stream
+  participant Worker as Stream Worker
+  participant Mongo as MongoDB
+  participant Pg as Postgres
+  participant Web as Web UI
+
+  loop every second for each active camera
+    Cam->>Ingest: create telemetry event
+    Ingest->>Stream: XADD telemetry stream
+    Ingest-->>Cam: accepted when enqueue succeeds
+  end
+
+  loop worker processing
+    Worker->>Stream: XREADGROUP
+    Worker->>Mongo: insert raw telemetry
+    Worker->>Pg: upsert latest device current state
+    Worker->>Pg: insert snapshot if older than 5 seconds
+    Worker->>Stream: XACK
+    Note over Worker,Stream: retry up to three times then write to DLQ
+  end
+
+  loop web refresh every second
+    Web->>Ingest: GET cameras
+    Ingest->>Pg: read latest state
+    Ingest-->>Web: return camera rows with latest status
+  end
+```