Issue #, if available:
#1466

Description of changes:
Enables background server load:

• As described in Background server loading #1466, relegates tools/list to the same level as prompts, which are also fetched in the background.
• Enables users to set timeout for servers init, beyond which the stragglers continue to load in the background, enabling users to start typing. This is done via q settings mcp.initTimeout. I have opted to not have this in mcp.json because this might conflict with how IDE interprets the config.
• Enables users to interrupt server loading (even with timeout set) to immediately start conversation.
• /tools now show servers still in loading.

Removal of mcp_client crate:

• No longer needed since the refactor

Refinement of conversation invariant logic with regards to tool calls with incorrect names:
There are three scenarios in which intervention would be needed:

1. The model had decided to call a tool with its partial name AND there is only one such tool, in
   which case we would automatically resolve this tool call to its correct name. This will NOT
   result in an error in its tool result. The intervention here is to substitute the partial name
   with its full name.
2. The model had decided to call a tool with its partial name AND there are multiple tools it
   could be referring to, in which case we WILL return an error in the tool result. The
   intervention here is to substitute the ambiguous, partial name with a dummy.
3. The model had decided to call a tool that does not exist. The intervention here is to
   substitute the non-existent tool name with a dummy.

List changed support for prompts and tools:

• List changed support for prompts and tools.
• This is added because it is enabled by background server load.

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