hemictl: improve readme docs (#366)

* Update README.md

- Add missing environment variables documentation
- Improve code examples and formatting
- Add error handling section
- Reorganize content with clear sections
- Add usage notes and best practices
- Remove sensitive information

* Update README.md

* Update README.md

cmd/hemictl/README.md

@@ -1,36 +1,46 @@
 ## hemictl
 
-The `hemictl` command is a generic tool to script commands to the various
-daemons. The generic use is: `hemictl <daemon> <action> [json parameters]`.
+The `hemictl` command is a generic tool to script commands to various daemons.
 
-`daemon` determines the default URI `hemictl` connects to. E.g. `bss` is
-`ws://localhost:8081/v1/ws`.
+### Usage
+```bash
+hemictl <daemon> <action> [json parameters]
+```
 
-TODO: Add environment variable override for the URI.
+### Components
 
-`action` determines which command will be called. E.g. `ping`.
+- `daemon`: Determines the default URI `hemictl` connects to (e.g., `bss` connects to `ws://localhost:8081/v1/ws`)
+- `action`: Specifies which command will be called (e.g., `ping`)
+- `parameters`: JSON encoded parameters for the `action` (e.g., `{"timestamp":1}`)
 
-`parameters` are JSON encoded parameters to the `action`. E.g. `{"timestamp":1}`.
+### Environment Variables
 
-Thus a command to a daemon can be issues as such:
-```
+- `LOGLEVEL`: Sets the logging level (e.g., `INFO`, `DEBUG`)
+- `PGURI`: Override database connection URI for database operations
+- `HEMI_URI`: Override default daemon URI (format: `ws://host:port/v1/ws`)
+
+### Examples
+
+#### Basic Ping Command
+```bash
 hemictl bss ping '{"timestamp":1}'
 ```
 
-Which will result in something like:
-```
+Response:
+```json
 {
     "origintimestamp": 1,
     "timestamp": 1701091119
 }
 ```
 
-And example of a call with a failure:
-```
+#### Error Handling Example
+```bash
 hemictl bss l1tick '{"l1_height":0}'
 ```
 
-```
+Response:
+```json
 {
     "error": {
         "timestamp": 1701091156,
@@ -40,20 +50,33 @@ hemictl bss l1tick '{"l1_height":0}'
 }
 ```
 
-## database
-
-`hemictl` allows direct access to the storage layer. For now it only supports
-`postgres`.
+### Database Operations
 
+`hemictl` provides direct access to the storage layer, currently supporting PostgreSQL.
 
-```
+#### Check Database Version
+```bash
 hemictl bfgdb version
 ```
-```
+
+Response:
+```json
 {"bfgdb_version":1}
 ```
 
-Database URI may be overridden. E.g.:
-```
-LOGLEVEL=INFO PGURI="user=marco password=`cat ~/.pgsql-bfgdb-marco` database=bfgdb" ./bin/hemictl bfgdb version
+#### Custom Database Connection
+```bash
+LOGLEVEL=INFO PGURI="user=username password=secretpassword database=bfgdb" hemictl bfgdb version
 ```
+
+### Error Handling
+
+The tool provides detailed error messages with:
+- Timestamp of the error
+- Trace ID for debugging
+- Human-readable error message
+
+### Notes
+- Always ensure proper JSON formatting in parameters
+- Use appropriate environment variables for production deployments
+- Check logs when troubleshooting failed commands