* feat(#444): add MCP API endpoints and data models
- Add McpServer.status and McpServer.error fields for diagnostics
- Add AddMcpServerRequest, McpCatalogResponse/Entry/EnvVar models
- Add McpServerTestResponse model
- Add POST addMcpServer, PUT updateMcpServer, POST restartMcpServer
- Add GET getMcpCatalog, POST installMcpCatalogEntry
* feat(#444): add server form, enriched server cards, catalog section
- Add HTTP/stdio inline server form with tabs
- Enriched server cards with status badge, restart, env var editing
- Add/edit/remove environment variables per server
- Catalog section with search, result cards, install flow with env vars
- Status badge colors: running=green, error=red, stopped/gray
- Server diagnostics shown as error badges on cards
- New string resources for all MCP UI elements
* fix(#444): add missing McpServer import to HermesApiService
* fix(#444): cleanup review issues — dead code, spinner, unused strings
- Remove unused serverDiagnostics from UiState
- Remove unused showDiagnostics local state in ServerCard
- Remove unused McpServerTestResponse model
- Remove redundant refreshDiagnostics() alias
- Replace catalog loading text with CircularProgressIndicator
- Remove unused string resources (action_restarting, diagnostics, catalog_load)
* fix(#444): remove remaining showDiagnostics reference at line 348
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Co-authored-by: Hermes Agent <hermes@agent.local>
