fix: add missing serde default to list_format field

Fixes deserialization failure in generate-config mode by adding
#[serde(default)] attribute to list_format field in Settings struct.
This allows the config library to provide sensible defaults when
no config file exists, resolving the error "missing field list_format".

Also unstages AGENT.md naming change since that's a different fix.

AGENTS.md

@@ -0,0 +1,84 @@
+# Agent Configuration
+
+**IMPORTANT:** Prefer to use the `write_file` tool if the edit is for the majority of a file, or if you are correcting previous problems made edits from other tools.
+
+## Tools
+
+**IMPORTANT**: Be very careful when quoting text in tool calls to add the right amount of escaping.
+
+### `write_file`
+
+When editing files use the `write_file` tool to output the complete version of the corrected file.
+**IMPORTANT**: You must provide the whole file to `write_file`, even the unchanged parts.
+
+## Build/Test Commands
+
+**IMPORTANT**: Do not run application, start the web server, or the trunk server.
+**IMPORTANT:** The cargo command cannot be ran in parallel.
+
+```bash
+# Check project
+TERM=dumb cargo check
+
+# Build project
+TERM=dumb cargo build
+
+# DO NOT RUN RUN APPLICATION (native)
+# TERM=dumb cargo run
+
+# Run all tests
+TERM=dumb cargo test
+
+# Run specific test (by name substring)
+TERM=dumb cargo test test_function_name
+
+# Run specific test with verbose output
+TERM=dumb cargo test test_function_name -- --nocapture
+
+# Check formatting
+TERM=dumb cargo fmt --check
+
+# Apply formatting
+TERM=dumb cargo fmt
+
+# Lint with clippy
+TERM=dumb cargo clippy -- -D warnings
+
+# Build for release
+TERM=dumb cargo build --release
+```
+
+Prefix commands with `TERM=dumb` for consistent output.
+
+## Code Style Guidelines
+
+### Imports
+- Group imports in order: standard library, external crates, local modules
+- Use explicit imports over glob imports (`use std::fs::File;` not `use std::fs::*;`)
+
+### Documentation
+- Document all public APIs with rustdoc
+- Use examples in documentation only when helpful
+
+## Procedures
+
+### Fix build problems
+
+1. Check the project: `TERM=dumb cargo check`.
+2. If there are errors or warnings, create a new sub agent (expert rust developer) that uses the `TERM=dumb cargo check` output as input, planned using strategic thinking.
+   a. Read all affected files
+   d. Plan the fixes using strategic thinking:
+      - Read other files if they provide context or examples
+      - Look up relevant API information
+      - Do not downgrade versions
+      - Preserve functionality
+      - Use `TERM=dumb cargo fix` if appropriate.
+      - Prefer the `write_file` tool if there is evidence of double escaping
+      - You must generate the full file contents when using `write_file` or it will be truncated.
+   c. Return the list of files modified
+3. If any files were modified, loop back to 1.
+
+### Fix formatting
+
+1. Format the project the project: `TERM=dumb cargo fmt`
+2. Continue with the fix build problems procedure.