Refactor: Code cleanup and localStorage consolidation

This commit includes comprehensive codebase cleanup and refactoring:

## Code Cleanup
- Remove dead TypeScript code (types/monitoring.ts - 194 lines duplicate)
- Remove unused Go functions (GetClusterNodes, MigratePassword, GetClusterHealthInfo)
- Clean up commented-out code blocks across multiple files
- Remove unused TypeScript exports (helpTextClass, private tag color helpers)
- Delete obsolete test files and components

## localStorage Consolidation
- Centralize all storage keys into STORAGE_KEYS constant
- Update 5 files to use centralized keys:
  * utils/apiClient.ts (AUTH, LEGACY_TOKEN)
  * components/Dashboard/Dashboard.tsx (GUEST_METADATA)
  * components/Docker/DockerHosts.tsx (DOCKER_METADATA)
  * App.tsx (PLATFORMS_SEEN)
  * stores/updates.ts (UPDATES)
- Benefits: Single source of truth, prevents typos, better maintainability

## Previous Work Committed
- Docker monitoring improvements and disk metrics
- Security enhancements and setup fixes
- API refactoring and cleanup
- Documentation updates
- Build system improvements

## Testing
- All frontend tests pass (29 tests)
- All Go tests pass (15 packages)
- Production build successful
- Zero breaking changes

Total: 186 files changed, 5825 insertions(+), 11602 deletions(-)

docs/CONFIGURATION.md

@@ -286,7 +286,7 @@ PROXY_AUTH_LOGOUT_URL=/logout        # URL for SSO logout
 - Set a metric to `-1` to disable it globally or per-resource (the UI shows “Off” and adds a **Custom** badge).
 - `timeThresholds` apply a grace period before an alert fires; `metricTimeThresholds` allow per-metric overrides (e.g., delay network alerts longer than CPU).
 - `overrides` are indexed by the stable resource ID returned from `/api/state` (VMs: `instance/qemu/vmid`, containers: `instance/lxc/ctid`, nodes: `instance/node`).
-- `dockerIgnoredContainerPrefixes` lets you silence state/metric/restart alerts for ephemeral containers whose names or IDs share a common, case-insensitive prefix. The Docker tab in the UI keeps this list in sync.
+- `dockerIgnoredContainerPrefixes` lets you silence state/metric/restart alerts for ephemeral containers whose names or IDs share a common, case-insensitive prefix. The Containers tab in the UI keeps this list in sync.
 - Swarm service alerts track missing replicas: `serviceWarnGapPercent` defines when a warning fires, and `serviceCriticalGapPercent` must be greater than or equal to the warning gap (Pulse automatically clamps the critical value upward if an older client submits something smaller).
 - Docker container state controls live in `dockerDefaults`: flip `stateDisableConnectivity` to silence exit/offline alerts globally, or change `statePoweredOffSeverity` to `critical` when you want exiting containers to page immediately. Per-container overrides still take precedence.
 - `dockerDefaults.disk` defines the writable-layer usage threshold (% of the container's upper filesystem compared to its base image). Defaults trigger at 85% and clear at 80%, and can be overridden per container or host when noisy workloads need a different window.