feat(#439): enrich sessions tab with dashboard features (#460)

* feat(#439): enrich sessions tab with dashboard features

Add session stats (total/active counts), per-session source icons,
active session badges, inline rename, bulk selection with toolbar,
prune old sessions dialog with configurable days threshold,
session prompt copy, single-session delete, and search highlighting.

- SessionInfo model: add source field
- New models: SessionStatsResponse, SessionRenameRequest,
  BulkDeleteRequest, PruneRequest, SessionPromptResponse
- HermesApiService: add stats, rename, bulk delete, prune, prompt endpoints
- SessionsViewModel: stats loading, bulk select, rename, delete, prune
- SessionsScreen: stats row, source icons, active border, rename inline,
  bulk mode with animated toolbar, prune dialog, search highlight
- strings.xml: new resources for all sessions UI features

* fix(#439): resolve CI compile errors

- Add explicit icon imports for Code, Language, Terminal
- Add missing clickable import
- Make highlightText non-composable by passing color params
- Fix combinedClickable usage on SessionCard

* fix(#439): address review findings

- Remove unused background import
- Add dedicated DELETE /api/sessions/{id} endpoint
- Refactor deleteSession to use dedicated endpoint
- Add confirmation dialogs for both single-session and bulk delete
- Surface statsError in the UI when stats load fails
- Add string resources for delete confirmation dialogs

* fix(#439): fix delegated property smart cast errors

- Capture statsError, errorMessage, sessionToDeleteConfirm in local vals
  before null checks to avoid 'Smart cast impossible' on delegated props

* fix(#439): remove copy and rename buttons, keep delete only

* fix(#439): restore CheckCircle import

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/data/model/SessionListResponse.kt

@@ -15,4 +15,28 @@ data class SessionInfo(
     val status: String?,
     val preview: String? = null,
     val started_at: Double? = null,
+    val source: String? = null,
+)
+
+data class SessionStatsResponse(
+    val total: Int = 0,
+    val active: Int = 0,
+)
+
+data class SessionRenameRequest(
+    val title: String,
+)
+
+data class BulkDeleteRequest(
+    val ids: List<String>,
+    val delete_all: Boolean = false,
+)
+
+data class PruneRequest(
+    val days: Int,
+)
+
+data class SessionPromptResponse(
+    val prompt: String? = null,
+    val id: String? = null,
 )