Invalid mcp.json silently fails

### Checks

- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my issue
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again

### Operating system

macOS 15.6.1 (24G90)

### Expected behaviour

If there is an issue with mcp.json, those should be reported on q chat startup

### Actual behaviour

IF you have a syntax error in your mcp.json file (so the json is invalid) launching q chat fails to start any MCP server, and fails to say why.

### Steps to reproduce

remove a comma or curly brace from your mcp.json. Start q chat. Run /mcp and view the output.

### Environment

```yaml

[q-details]
version = "1.14.1"
hash = "209dfbf9c7bd73473a6712f3351158323f28e173"
date = "2025-08-21T18:25:42.366538Z (7d ago)"

[system-info]
os = "macOS 15.6.1 (24G90)"
chip = "Apple M1"
total-cores = 8
memory = "16.00 GB"

[environment]
cwd = "/Users/USER"
cli-path = "/Users/USER"
install-method = "unknown"

[env-vars]
PATH = "/Users/USER/Library/pnpm:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Library/Apple/usr/bin:/Users/USER/.local/bin:/Users/USER/.toolbox/bin"
QTERM_SESSION_ID = "c7329fb482ab4138a625ce1c5ddcc21f"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "1.14.1"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.apple.Terminal"

[chat-settings]

[chat-trusted_tools]
fs_read=trusted
@outlook-mcp-server/unified_email_search=trusted
@outlook-mcp-server/get_email_content=trusted

[chat-failed_request_ids]
none

[chat-context]
current_profile=q_cli_default
profile_context=
AmazonQ.md
README.md
.amazonq/rules/**/*.md

files=none
```