Add settings UI, Discord notifications, and alert detail improvements

- Settings modal (gear icon) lets you configure all service URLs and API
  keys from the dashboard; values persist to data/settings.json with
  process.env as fallback so existing .env.local setups keep working
- Per-service Test button hits each service's status endpoint and reports
  the version on success
- Discord webhook support: structured embeds per alert category (requesters,
  approval age, episode progress, watch-rate stats) sent on new/reopened
  alerts only — already-open alerts don't re-notify
- Alert detail page restructured: prose descriptions replaced with labelled
  fields, episode progress bar for partial TV, watch-rate stat block,
  View in Radarr/Sonarr/Seerr action buttons, requester names link to
  Overseerr profiles, timestamps moved inline with status
- Tab state is pure client state (no ?tab= in URL); router.back() used
  on alert detail for clean browser history

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -10,6 +10,8 @@ Built with Next.js 16, TypeScript, and Tailwind CSS.
 
 - **Leaderboard** — per-user request count, total storage, average GB per request, and optional Tautulli watch stats (plays, watch hours), each ranked against the full userbase
 - **Alerting** — automatic alerts for stalled downloads, neglected requesters, and abusive patterns, with open/close state, notes, and auto-resolve when conditions clear
+- **Discord notifications** — posts a structured embed to a webhook whenever a new alert opens or a resolved one returns
+- **Settings UI** — configure all service URLs and API keys from the dashboard; no need to touch `.env.local` after initial setup
 - **SWR caching** — stats are cached server-side for 5 minutes and seeded from localStorage on the client, so the dashboard is instant on return visits
 
 ---
@@ -24,9 +26,21 @@ cd OverSnitch
 npm install
 ```
 
-### 2. Configure environment
+### 2. Configure
 
-Create `.env.local` in the project root:
+**Option A — Settings UI (recommended)**
+
+Start the app and click the gear icon in the top-right corner. Enter your service URLs and API keys, hit **Test** to verify each connection, then **Save**.
+
+```bash
+npm run dev      # or: npm run build && npm start
+```
+
+Settings are written to `data/settings.json` (gitignored).
+
+**Option B — Environment variables**
+
+Create `.env.local` in the project root. Values here are used as fallbacks when `data/settings.json` doesn't exist or doesn't contain an override.
 
 ```env
 # Required
@@ -43,22 +57,38 @@ SONARR_API=your_sonarr_api_key
 TAUTULLI_URL=http://tautulli:8181
 TAUTULLI_API=your_tautulli_api_key
 
+# Optional — Discord webhook for new-alert notifications
+DISCORD_WEBHOOK=https://discord.com/api/webhooks/...
+
 # Optional — if your services use self-signed certs
 # NODE_TLS_REJECT_UNAUTHORIZED=0
 ```
 
-### 3. Run
+---
 
-```bash
-npm run dev                      # development
-npm run build && npm start       # production
-```
+## Discord Notifications
+
+When configured, OverSnitch posts a structured embed to your Discord channel whenever an alert is newly opened or reopens after being resolved. Already-open alerts refreshing their data do not re-notify.
+
+Each embed is formatted by category:
+
+| Category | Fields shown |
+|---|---|
+| Not Downloaded | Requested by · Approved N ago · Status |
+| Incomplete Download | Requested by · Approved N ago · Downloaded X/Y episodes |
+| Pending Approval | Requested by · Waiting N days |
+| Ghost Requester | User · description |
+| Low Watch Rate | User · Watch rate · Plays · Requests |
+
+Configure the webhook URL in the Settings UI or via `DISCORD_WEBHOOK` in `.env.local`. Use the **Test** button to send a sample embed before saving.
 
 ---
 
 ## Alerts
 
-Alerts are generated on every stats refresh and persisted in `data/alerts.json` (gitignored). They have two states — **Open** and **Closed** — and can be manually closed with a per-category cooldown, or auto-resolved when the underlying condition clears.
+Alerts are generated on every stats refresh and persisted in `data/alerts.db` (SQLite, gitignored). They have two states — **Open** and **Closed** — and can be manually closed with a per-category cooldown, or auto-resolved when the underlying condition clears.
+
+The alert detail page shows structured metadata (requesters, age, episode progress bars, watch-rate stats), direct links to the item in Radarr/Sonarr, a link to the Overseerr/Jellyseerr media page, and a comment thread for notes.
 
 ### Content alerts