* feat(#442): categorized env keys screen with add/remove, search, and gateway restart
- Group env vars by category (LLM Providers, Tool API Keys, Messaging
Platforms, Agent Settings, Other) with collapsible AnimatedVisibility
sections matching MCP screen pattern
- Add new env var form (PUT /api/env) with key/value inputs
- Delete env var via DELETE /api/env with EnvVarDeleteRequest body
- Reveal/hide/edit inline per-card controls
- Search bar filtering across key names and descriptions
- Gateway restart banner with one-click action when changes are dirty
- Track keysChanged flag showing restart prompt after mutations
- Wire delete endpoint in HermesApiService using @HTTP(hasBody=true)
- Add EnvVarDeleteRequest data model class
* fix(#442): update test to match new categorized KeysViewModel API
* fix(#442): satisfy ktlint multiline-expression-wrapping rule
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Co-authored-by: Hermes Agent <hermes@agent.local>
