# Description
Adds back the `to_ascii_lowercase` deleted in #13802. Also fixes the
error messages having the lowercased value instead of the original
value.

# Release-Notes Short Description

* Nushell now always loads its internal `default_env.nu` before the user
`env.nu` is loaded, then loads the internal `default_config.nu` before
the user's `config.nu` is loaded. This allows for a simpler
user-configuration experience. The Configuration Chapter of the Book
will be updated soon with the new behavior.

# Description

Implements the main ideas in #13671 and a few more:

* Users can now specify only the environment and config options they
want to override in *their* `env.nu` and `config.nu`and yet still have
access to all of the defaults:
* `default_env.nu` (internally defined) will be loaded whenever (and
before) the user's `env.nu` is loaded.
* `default_config.nu` (internally defined) will be loaded whenever (and
before) the user's `config.nu` is loaded.
* No more 900+ line config out-of-the-box.
* Faster startup (again): ~40-45% improvement in launch time with a
default configuration.
* New keys that are added to the defaults in the future will
automatically be available to all users after updating Nushell. No need
to regenerate config to get the new defaults.
* It is now possible to have different internal defaults (which will be
used with `-c` and scripts) vs. REPL defaults. This would have solved
many of the user complaints about the [`display_errors`
implementation](https://www.nushell.sh/blog/2024-09-17-nushell_0_98_0.html#non-zero-exit-codes-are-now-errors-toc).
* A basic "scaffold" `config.nu` and `env.nu` are created on first
launch (if the config directory isn't present).
* Improved "out-of-the-box" experience (OOBE) - No longer asks to create
the files; the minimal scaffolding will be automatically created. If
deleted, they will not be regenerated. This provides a better
"out-of-the-box" experience for the user as they no longer have to make
this decision (without much info on the pros or cons) when first
launching.
* <s>(New: 2024-11-07) Runs the env_conversions process after the
`default_env.nu` is loaded so that users can treat `Path`/`PATH` as
lists in their own config.</s>
* (New: 2024-11-08) Given the changes in #13802, `default_config.nu`
will be a minimal file to minimize load-times. This shaves another (on
my system) ~3ms off the base launch time.
* Related: Keybindings, menus, and hooks that are already internal
defaults are no longer duplicated in `$env.config`. The documentation
will be updated to cover these scenarios.
* (New: 2024-11-08) Move existing "full" `default_config.nu` to
`sample_config.nu` for short-term "documentation" purposes.
* (New: 2024-11-18) Move the `dark-theme` and `light-theme` to Standard
Library and demonstrate their use - Also improves startup times, but
we're reaching the limit of optimization.
* (New: 2024-11-18) Extensively documented/commented `sample_env.nu` and
`sample_config.nu`. These can be displayed in-shell using (for example)
`config nu --sample | nu-highlight | less -R`. Note: Much of this will
eventually be moved to or (some) duplicated in the Doc. But for now,
this some nice in-shell doc that replaces the older
"commented/documented default".
* (New: 2024-11-20) Runs the `ENV_CONVERSIONS` process (1) after the
`default_env.nu` (allows `PATH` to be used as a list in user's `env.nu`)
and (2) before `default_config.nu` is loaded (allows user's
`ENV_CONVERSIONS` from their `env.nu` to be used in their `config.nu`).
* <s>(New: 2024-11-20) The default `ENV_CONVERSIONS` is now an empty
record. The internal Rust code handles `PATH` (and variants) conversions
regardless of the `ENV_CONVERSIONS` variable. This shaves a *very* small
amount of time off the startup.</s> Reset - Looks like there might be a
bug in `nu-enginer::env::ensure_path()` on Windows that would need to be
fixed in order for this to work.

# User-Facing Changes

By default, you shouldn't see much, if any, change when running this
with your existing configuration.

To see the greatest benefit from these changes, you'll probably want to
start with a "fresh" config. This can be easily tested using something
like:

```nushell
let temp_home = (mktemp -d)
$env.XDG_CONFIG_HOME = $temp_home
$env.XDG_DATA_HOME = $temp_home
./target/release/nu
```

You should see a message where the (mostly empty) `env.nu` and
`config.nu` are created on first start. Defaults should be the same (or
similar to) those before the PR. Please let me know if you notice any
differences.

---

Users should now specify configuration in terms of overrides of each
setting. For instance, rather than modifying `history` settings in the
monolithic `config.nu`, the following is recommended in an updated
`config.nu`:

```nu
$env.config.history = {
  file_format: sqlite,
  sync_on_enter: true
  isolation: true
  max_size: 1_000_000
}
```

or even just:

```nu
$env.config.history.file_format = sqlite
$env.config.history.isolation: true
$env.config.history.max_size = 1_000_000
```

Note: It seems many users are already appending a `source my_config.nu`
(or similar pattern) to the end of the existing `config.nu` to make
updates easier. In this case, they will likely want to remove all of the
previous defaults and just move their `my_config.nu` to `config.nu`.

Note: It should be unlikely that there are any breaking changes here,
but there's a slim chance that some code, somewhere, *expects* an
absence of certain config values. Otherwise, all config values are
available before and after this change.

# Tests + Formatting

- :green_circle: `toolkit fmt`
- :green_circle: `toolkit clippy`
- :green_circle: `toolkit test`
- :green_circle: `toolkit test stdlib`

# After Submitting

Configuration Chapter (and related) of the doc is currently WIP and will
be finished in time for 0.101 release.

# Description

As a bit of a follow-on to #13802 and #14249, this (pretty much a
"one-line" change) really does *always* populate the `$env.config`
record with the `nu-protocol::config` defaults during startup. This
means that an `$env.config` record is value (with defaults) even during:

* `nu -n` to suppress loading of config files
* `nu -c <commandstring>`
* `nu <script>`

# User-Facing Changes

There should be no case in which there isn't a valid `$env.config`.

* Before:

  ```nushell
  nu -c "$env.config"
  # -> Error
  ```

* After:

  ```nushell
  nu -c "$env.config"
  # -> Default $env.config record
  ```

Startup time impact is negligible (17.072µs from `perf!` on my system) -
Seems well worth it.

# Tests + Formatting

Added tests for several `-n -c` cases.

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting

Config chapter update still in progress.