major: kestrel is now a tak server (#6)

## Added

- CoT (Cursor on Target) server on port 8089 enabling ATAK/iTAK device connectivity
- Support for TAK stream protocol and traditional XML CoT messages
- TLS/SSL support with automatic fallback to plain TCP
- Username/password authentication for CoT connections
- Real-time device position tracking with TTL-based expiration (90s default)
- API endpoints: `/api/cot/config`, `/api/cot/server-package`, `/api/cot/truststore`, `/api/me/cot-password`
- TAK Server section in Settings with QR code for iTAK setup
- ATAK password management in Account page for OIDC users
- CoT device markers on map showing real-time positions
- Comprehensive documentation in `docs/` directory
- Environment variables: `COT_PORT`, `COT_TTL_MS`, `COT_REQUIRE_AUTH`, `COT_SSL_CERT`, `COT_SSL_KEY`, `COT_DEBUG`
- Dependencies: `fast-xml-parser`, `jszip`, `qrcode`

## Changed

- Authentication system supports CoT password management for OIDC users
- Database schema includes `cot_password_hash` field
- Test suite refactored to follow functional design principles

## Removed

- Consolidated utility modules: `authConfig.js`, `authSkipPaths.js`, `bootstrap.js`, `poiConstants.js`, `session.js`

## Security

- XML entity expansion protection in CoT parser
- Enhanced input validation and SQL injection prevention
- Authentication timeout to prevent hanging connections

## Breaking Changes

- Port 8089 must be exposed for CoT server. Update firewall rules and Docker/Kubernetes configurations.

## Migration Notes

- OIDC users must set ATAK password via Account settings before connecting
- Docker: expose port 8089 (`-p 8089:8089`)
- Kubernetes: update Helm values to expose port 8089

Co-authored-by: Madison Grubb <madison@elastiflow.com>
Reviewed-on: #6

server/utils/constants.js

@@ -0,0 +1,30 @@
+/**
+ * Application constants with environment variable support.
+ */
+
+// Timeouts (milliseconds)
+export const COT_AUTH_TIMEOUT_MS = Number(process.env.COT_AUTH_TIMEOUT_MS) || 15_000
+export const LIVE_SESSION_TTL_MS = Number(process.env.LIVE_SESSION_TTL_MS) || 60_000
+export const COT_ENTITY_TTL_MS = Number(process.env.COT_ENTITY_TTL_MS) || 90_000
+export const POLL_INTERVAL_MS = Number(process.env.POLL_INTERVAL_MS) || 1500
+export const SHUTDOWN_TIMEOUT_MS = Number(process.env.SHUTDOWN_TIMEOUT_MS) || 30_000
+
+// Ports
+export const COT_PORT = Number(process.env.COT_PORT) || 8089
+export const WEBSOCKET_PATH = process.env.WEBSOCKET_PATH || '/ws'
+
+// Limits
+export const MAX_PAYLOAD_BYTES = Number(process.env.MAX_PAYLOAD_BYTES) || 64 * 1024
+export const MAX_STRING_LENGTH = Number(process.env.MAX_STRING_LENGTH) || 1000
+export const MAX_IDENTIFIER_LENGTH = Number(process.env.MAX_IDENTIFIER_LENGTH) || 255
+
+// Mediasoup
+export const MEDIASOUP_RTC_MIN_PORT = Number(process.env.MEDIASOUP_RTC_MIN_PORT) || 40000
+export const MEDIASOUP_RTC_MAX_PORT = Number(process.env.MEDIASOUP_RTC_MAX_PORT) || 49999
+
+// Session
+const [MIN_DAYS, MAX_DAYS, DEFAULT_DAYS] = [1, 365, 7]
+export function getSessionMaxAgeDays() {
+  const raw = Number.parseInt(process.env.SESSION_MAX_AGE_DAYS ?? '', 10)
+  return Number.isFinite(raw) ? Math.max(MIN_DAYS, Math.min(MAX_DAYS, raw)) : DEFAULT_DAYS
+}