Delegate tool fs_write permission denied - delegates interpret write attempts as "rejection"

### 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 15.7.0 (24G222)

### Expected behaviour

Delegates should be able to use fs_write tool to create files when configured with readonly: false, especially when the same fs_write operations work perfectly when executed directly by the main agent.

### Actual behaviour

When using Delegate tool with readonly: false, delegates can successfully read files and analyze data, but when they attempt to use fs_write to create files, they report "file creation has been rejected" and refuse to proceed. The delegates appear to be interpreting some permission prompt or access control as user rejection.

```
[chat-transcript]
The `report_issue` tool opens a pre-fill

> ok i've updated the agent again... can you do a simple delegation like this: "Please check your style tools and find and understand the rules in this json file . Create the test file for it in the appropriate folder in the ./test_content folder."

[Tool uses: Delegate]

The delegate is still interpreting something as rejection, but this time it actually did the analysis work! It:

1. ✅ Found and read the JSON file
2. ✅ Identified rule 30013 correctly
3. ✅ Located the appropriate test folder
4. ✅ Noticed the missing file
5. ❌ Still thinks file creation was "rejected"

This suggests the delegate tools are working now, but there's still some permission/trust issue specifically with file writing. The delegate can read files and analyze data, but when it tries to write, it gets blocked.

The analysis part is working perfectly though - it correctly identified the missing rule and understood the task structure!
[Tool uses: none]

> did you launch the specified agent?

No, I used the `Delegate` tool, not the `handoff` tool.

`Delegate` creates a new AI instance on-demand - it doesn't launch or connect to a specific tcx/style-tester agent.

`handoff` would try to connect to a running tcx/style-tester agent in tmux, but that failed earlier because no such agent was running.

Did you want me to try `handoff` to the tcx/style-tester agent instead? That would require the agent to be actively running in a tmux session first.
[Tool uses: none]

> no please tell me more about the Delegate options

## Delegate Tool Configuration Options

### **Configuration Parameters**
\```json
"configuration": {
"modelArn": "model-identifier",
"parallel": true/false,
"readonly": true/false
}
\```

### **Key Options:**

**`readonly`** (boolean)
- `true`: Read-only mode, automatically allows parallel execution
- `false`: Write mode, runs sequentially by default
- **Default**: false

**`parallel`** (boolean)
- `true`: Forces parallel execution (disables custom tools unless auto-accept-edits enabled)
- `false`: Sequential execution
- **Default**: false for write operations, true for readonly

**`modelArn`** (string)
- Specify different AI models per delegate
- **Default**: `anthropic.claude-3-5-haiku-20241022-v1:0`
- Options include Claude Sonnet, Opus, Nova models

### **Dependencies**
**`dependentIdentifiers`** (array)
- List of delegate IDs that must complete first
- Results from dependencies included in prompt
- Enables complex workflows with ordered execution

### **Current Issue**
The delegates are running in **write mode** (`readonly: false`) but seem to lack proper file write permissions, causing them to interpret permission prompts as "rejection."

**Possible solutions:**
1. Try `"readonly": true` for analysis tasks
2. Enable `"parallel": true` with auto-accept-edits
3. Use different model that might have different permissions
[Tool uses: none]

> neat... ok let's report this issue

[Tool uses: report_issue]

(...truncated)
```

### Steps to reproduce

1. Use Delegate tool with configuration readonly: false 2. In delegate prompt, instruct to create a file using fs_write 3. Delegate performs analysis correctly but reports "file creation rejected" when attempting fs_write 4. Same fs_write operation works fine when executed directly by main agent

### Environment

```yaml

[q-details]
version = "1.16.2"
hash = "c4c80bb44cb22b6e19129ed7475f2793ff20135d"
date = "2025-09-19T01:27:56.356289Z (9d ago)"

[system-info]
os = "macOS 15.7.0 (24G222)"
chip = "Apple M3 Pro"
total-cores = 12
memory = "36.00 GB"

[environment]
cwd = "/Volumes/workplace/FusionAgents/src/FusionAgentRegistry/tcx/style-tester"
cli-path = "/Volumes/workplace/FusionAgents/src/FusionAgentRegistry/tcx/style-tester"
install-method = "toolbox"

[env-vars]
PATH = "/Users/USER/.local/share/mise/installs/node/18.20.2/bin:/Users/USER/.local/share/mise/installs/python/3.12.4/bin:/Users/USER/.local/share/mise/installs/python/3.11.9/bin:/Users/USER/.local/share/mise/installs/python/3.10.14/bin:/Users/USER/.local/share/mise/installs/python/3.9.19/bin:/Users/USER/.local/share/mise/installs/python/3.8.19/bin:/Users/USER/.local/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/Users/USER/bin:/Users/USER/.toolbox/bin:/Users/USER/.local/bin:/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/TeX/texbin:/Users/USER/.cargo/bin:/Applications/Visual Studio Code.app/Contents/Resources/app/bin"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.apple.Terminal"

[chat-settings]

[chat-trusted_tools]
execute_bash=trusted
@builder-mcp/Delegate=trusted

[chat-failed_request_ids]
none

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

files=none
```