feat(#216): dynamic command autocomplete from server catalog, remove stop button (#403)

* feat(#216): dynamic command autocomplete from server catalog, remove stop button

- Replace hardcoded 8-command autocomplete with dynamic catalog from server's commands.catalog RPC
- Show ALL commands including skills via commandCatalog.pairs
- Remove physical Stop button (use /stop or /interrupt slash commands instead)
- Remove onInterrupt callback from ChatInputBar

* fix(#216): hide /stop and /interrupt from slash suggestions, remove stale strings

- Filters /stop and /interrupt from autocomplete popup while keeping
  them functional when manually typed
- Drops 7 unused command description string resources (now from server
  catalog) plus unused interrupt string resource

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

app/src/main/res/values/strings.xml

@@ -91,16 +91,8 @@
     <string name="chat_tool_fallback">Tool</string>
     <string name="chat_tool_show_raw">Show Raw JSON</string>
     <string name="chat_tool_show_parsed">Show Parsed Output</string>
-    <string name="command_help_desc">Show help menu</string>
-    <string name="command_status_desc">Check gateway and platform status</string>
-    <string name="command_sessions_desc">List all chat sessions</string>
-    <string name="command_stats_desc">Check system resource usage (stats)</string>
-    <string name="command_system_desc">Check system resource usage (system)</string>
-    <string name="command_new_desc">Create a new chat session</string>
-    <string name="command_stop_desc">Interrupt the active run</string>
     <string name="content_desc_new_chat">New Chat</string>
     <string name="content_desc_scroll_to_bottom">Scroll to bottom</string>
-    <string name="content_desc_interrupt">Interrupt</string>
     <string name="content_desc_copy">Copy</string>
     <string name="content_desc_edit">Edit</string>