docs: Update project and agent documentation.

- Document agent guidelines for asset tracking, including build commands, code style, data conventions, and security practices.
- Document project setup, features, configuration, usage, and output details for an asset tracking tool.

AGENTS.md

@@ -0,0 +1,29 @@
+# Asset Tracker - Agent Guidelines
+
+## Build/Test Commands
+- Run asset extraction: `./extract_assets.sh`
+- Generate charts: `./chart_asset_data.sh`
+- Full pipeline with SSH agent: `./run_with_agent.sh`
+- Test individual users: Edit `user_ids.conf` to modify USER_IDS array
+
+## Code Style Guidelines
+- Use bash for shell scripts with `#!/bin/bash` shebang
+- Source configuration files with `source ./user_ids.conf`
+- Use uppercase for global variables: `USER_IDS`, `URL_TEMPLATE`, `OUTPUT_DIR`
+- Function names in lowercase with underscores: `process_user()`
+- Use local variables in functions: `local USER_ID="$1"`
+- Error checking with conditional statements and proper exit codes
+- Clean up temporary files with `rm -f`
+- Use descriptive variable names: `png_total_assets`, `temp_diamonds_on_hand`
+
+## Data Conventions
+- CSV format: `date,rank,diamonds,total_assets`
+- Date format: `"%Y-%m-%d %H:%M:%S"`
+- Remove commas from numeric values with `tr -d ','`
+- Gnuplot time format: `"%Y-%m-%d"`
+- Output PNG files: `total_assets_${USER_ID}.png`, `diamonds_on_hand_${USER_ID}.png`
+
+## Security
+- Use SSH agent for key management: `ssh-add ~/.ssh/id_ed25519`
+- Handle sensitive URLs and paths in configuration files
+- Validate file existence before processing: `[ ! -f "$input_file" ]`