readme: extend, reword, add sections [skip ci]

README.md

@@ -25,6 +25,18 @@
 </p>
 
 
+### Who is this good for
+
+it might come in handy to anybody willing to operate this application for
+family, a group of friends, a university faculty or even just for themselves.
+
+### What even is this
+
+Password Compromise Monitoring Tool offers a frictionless way to check
+credentials for potential compromise. of course, the application cannot
+possibly know it all, which is why no indication of compromise does not
+necessarily amount to no compromise.
+
 ### How to try this out
 
 with [`podman`](https://podman.io/) and [`just`](https://github.com/casey/just)
@@ -97,24 +109,40 @@ config](exampleConfig.dhall).
 If you're new to Dhall, its [documentation](https://docs.dhall-lang.org/) page
 is a good resource to start at.
 
+### Run modes
+
+there are toggles that affect how the application behaves, and they can both be
+supplied either as environment variables prefixed with `PCMT_` or in the
+configuration file:
+* `LiveMode`
+* `DevelMode`
+
+live mode makes the application load all assets from persistent storage, i.e.
+it **no** assets embedded at build time are used (so make sure to supply your
+own).
+
+devel mode is mainly useful in development or when debugging. it makes the
+application reload the templates at every request and automatically increases
+log levels.
+
 ### 🔨 Building from sources
 
 pre-requisites:
-* [`just`](https://github.com/casey/just)
+* [`just`](https://github.com/casey/just) (for convenience)
 * [`npm`](https://docs.npmjs.com/cli/v9/)
 * [`go1.20`](https://go.dev/)
 * `git`
 
 the application consists of *frontend* and *backend*. the *frontend* is
 basically a **generated** TailwindCSS stylesheet and it is not shipped as part
-of the development process. as such, it needs to be built from sources, same as
+of the development process. as such, it needs to be built from sources just the
-the backend.
+same as the backend.
 
 **step 0:** clone this repository with `git`
 
-then build the *frontend* using `just tw` or `just frontend`
+**step 1:** build the *frontend* using `just tw` or `just frontend`
 
-next, build the Go application using:
+**step 2:** finally, build the Go application using:
 ```sh
 # debugging version.
 just build
@@ -123,16 +151,18 @@ just build
 just buildrelease
 ```
 
-alternatively, build both *frontend* and *backend* in release modes using:
+**step 1-alt:** build both *frontend* and *backend* in release modes using:
-`just prod`. the order of the steps is important as the application embeds the
+`just prod`.
-generated stylesheet.
+
+the order of the steps is important as the application embeds the generated
+stylesheet.
 
 if you plan to run the application in `LiveMode`, the stylesheet can be
 supplied when running the application; however, the binary will lack the way to
 fall back to the embedded asset so bear that in mind.
 
 if you're curious, you can open the [`justfile`](justfile) to see the details
-of the build targets like `tw` and `buildrelease` used above.
+of the build targets (such as `tw` and `buildrelease`) used above.
 
 
 ### LICENSE