1. Add `<overflow-menu>` web component
2. Rename `<gitea-origin-url>` to `<origin-url>` and make filenames
match.

<img width="439" alt="image"
src="https://github.com/go-gitea/gitea/assets/115237/2fbe4ca4-110b-4ad2-8e17-c1e116ccbd74">

<img width="444" alt="Screenshot 2024-03-02 at 21 36 52"
src="https://github.com/go-gitea/gitea/assets/115237/aa8f786e-dc8c-4030-b12d-7cfb74bdfd6e">

<img width="537" alt="Screenshot 2024-03-03 at 03 05 06"
src="https://github.com/go-gitea/gitea/assets/115237/fddd50aa-adf1-4b4b-bd7f-caf30c7b2245">


![image](https://github.com/go-gitea/gitea/assets/115237/0f43770c-834c-4a05-8e3d-d30eb8653786)


![image](https://github.com/go-gitea/gitea/assets/115237/4b4c6bd7-843f-4f49-808f-6b3aed5e9f9a)

TODO:

- [x] Check if removal of `requestAnimationFrame` is possible to avoid
flash of content. Likely needs a `MutationObserver`.
- [x] Hide tippy when button is removed from DOM.
- [x] ~~Implement right-aligned items
(https://github.com/go-gitea/gitea/pull/28976)~~. Not going to do it.
- [x] Clean up CSS so base element has no background and add background
via tailwind instead.
- [x] Use it for org and user page.

---------

Co-authored-by: Giteabot <teabot@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

In GitHub, we can not rerun jobs if the workflow is disabled.

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Very simple change, just rename this variable so it does not feature the
name of the module.

Clarify the "link-action" behavior:

>  // A "link-action" can post AJAX request to its "data-url"
> // Then the browser is redirect to: the "redirect" in response, or
"data-redirect" attribute, or current URL by reloading.

And enhance the "link-action" to support showing a modal dialog for
confirm. A similar general approach could also help PRs like
https://github.com/go-gitea/gitea/pull/22344#discussion_r1062883436

> // If the "link-action" has "data-modal-confirm(-html)" attribute, a
confirm modal dialog will be shown before taking action.


And a lot of duplicate code can be removed now. A good framework design
can help to avoid code copying&pasting.

---------

Co-authored-by: silverwind <me@silverwind.io>

It's been disabled by default since 1.17
(https://github.com/go-gitea/gitea/pull/18914), and it never really
delivered any benefit except being another cache layer that has its own
unsolved invalidation issues. HTTP cache works, we don't need two cache
layers at the browser for assets.

## :warning: BREAKING

You can remove the config `[ui].USE_SERVICE_WORKER` from your `app.ini`
now.

Partially for #24457

Major changes:

1. The old `signedUserNameStringPointerKey` is quite hacky, use
`ctx.Data[SignedUser]` instead
2. Move duplicate code from `Contexter` to `CommonTemplateContextData`
3. Remove incorrect copying&pasting code `ctx.Data["Err_Password"] =
true` in API handlers
4. Use one unique `RenderPanicErrorPage` for panic error page rendering
5. Move `stripSlashesMiddleware` to be the first middleware
6. Install global panic recovery handler, it works for both `install`
and `web`
7. Make `500.tmpl` only depend minimal template functions/variables,
avoid triggering new panics

Screenshot:

<details>

![image](https://user-images.githubusercontent.com/2114189/235444895-cecbabb8-e7dc-4360-a31c-b982d11946a7.png)

</details>

Close #24104

This also introduces many tests to cover many complex error handling
functions.

### Before

The details are never shown in production.

<details>

![image](https://user-images.githubusercontent.com/2114189/231805004-13214579-4fbe-465a-821c-be75c2749097.png)

</details>

### After

The details could be shown to site admin users. It is safe.

![image](https://user-images.githubusercontent.com/2114189/231803912-d5660994-416f-4b27-a4f1-a4cc962091d4.png)

The first step of the plan

* #23290

Thanks to @silverwind for the first try in #15394 . Close #10729 and a
lot of related issues.

The EasyMDE is not removed, now it works as a fallback, users can switch
between these two editors.

Editor list:

* Issue / PR comment
* Issue / PR comment edit
* Issue / PR comment quote reply
* PR diff view, inline comment
* PR diff view, inline comment edit
* PR diff view, inline comment quote reply
* Release editor
* Wiki editor

Some editors have attached dropzone

Screenshots:

<details>


![image](https://user-images.githubusercontent.com/2114189/229363558-7e44dcd4-fb6d-48a0-92f8-bd12f57bb0a0.png)


![image](https://user-images.githubusercontent.com/2114189/229363566-781489c8-5306-4347-9714-d71af5d5b0b1.png)


![image](https://user-images.githubusercontent.com/2114189/229363771-1717bf5c-0f2a-4fc2-ba84-4f5b2a343a11.png)


![image](https://user-images.githubusercontent.com/2114189/229363793-ad362d0f-a045-47bd-8f9d-05a9a842bb39.png)

</details>

---------

Co-authored-by: silverwind <me@silverwind.io>

This PR follows #22599 and #23450

The major improvements:

1. The `aria-*.js` are totally transparent now, no need to call
`attachDropdownAria` explicitly anymore.
* It hooks the `$.fn.checkbox` and `$.fn.dropdown`, then our patch
works.
* It makes all dynamically generated checkbox/dropdown work with a11y
without any change
* eg: the `conversation.find('.dropdown').dropdown();` in `repo-diff.js`
2. Since it's totally transparent now, it could be easier to modify or
remove in the future.
3. It handles all selection labels as well (by onLabelCreate), so it
supports "multiple selection dropdown" now.
* It partially completes one of my TODOs: `TODO: multiple selection is
not supported yet.`
4. The code structure is clearer, code blocks are splitted into
different functions.
* The old `attachOneDropdownAria` was splitted into separate functions.
* It makes it easier to add more fine tunes in the future, and co-work
with contributors.
6. The code logic is similar as before, only two new parts: 
    1. the `ariaCheckboxFn` and `ariaDropdownFn` functions
    2. the `onLabelCreate` and `updateSelectionLabel` functions

In `aria-dropdown.js` I had to mix jQuery and Vanilla JS somewhat, I
think the code is still understandable, otherwise the code would be much
more complex to read.

Thanks to fsologureng for the idea about "improving the 'delete icon'
with aria attributes".

If there is anything unclear or incorrect, feel free to ask and discuss,
or propose new PRs for it.

This PR follows:
* #21986
* #22831

This PR also introduce customized HTML elements, which would also help
problems like:
* #17760
* #21429
* #21440

With customized HTML elements, there won't be any load-search-replace
operations, and it can avoid page flicking (which @silverwind cares a
lot).

Browser support:
https://developer.mozilla.org/en-US/docs/Web/API/Window/customElements

# FAQ

## Why the component has the prefix?

As usual, I would strongly suggest to add prefixes for our own/private
names. The dedicated prefix will avoid conflicts in the future, and it
makes it easier to introduce various 3rd components, like GitHub's
`relative-time` component. If there is no prefix, it's impossible to
introduce another public component with the same name in the future.

## Why the `custcomp.js` is loaded before HTML body? The `index.js` is
after HTML body.

Customized components must be registered before the content loading.
Otherwise there would be still some flicking.

`custcomp.js` should have its own dependencies and should be very light,
so it won't affect the page loading time too much.

## Why use `data-url` attribute but not use the `textContent`?

According to the standard, the `connectedCallback` occurs on the
tag-opening moment. The element's children are not ready yet.

## Why not use `{{.GuessCurrentOrigin $.ctx ...}}` to let backend decide
the absolute URL?

It's difficult for backend to guess the correct protocol(scheme)
correctly with zero configuration. Generating the absolute URL from
frontend can guarantee that the URL is 100% correct -- since the user is
visiting it.

# Screenshot

<details>

![image](https://user-images.githubusercontent.com/2114189/218256757-a267c8ba-3108-4755-9ae5-329f1b08f615.png)

</details>

To avoid duplicated load of the same data in an HTTP request, we can set
a context cache to do that. i.e. Some pages may load a user from a
database with the same id in different areas on the same page. But the
code is hidden in two different deep logic. How should we share the
user? As a result of this PR, now if both entry functions accept
`context.Context` as the first parameter and we just need to refactor
`GetUserByID` to reuse the user from the context cache. Then it will not
be loaded twice on an HTTP request.

But of course, sometimes we would like to reload an object from the
database, that's why `RemoveContextData` is also exposed.

The core context cache is here. It defines a new context
```go
type cacheContext struct {
	ctx  context.Context
	data map[any]map[any]any
        lock sync.RWMutex
}

var cacheContextKey = struct{}{}

func WithCacheContext(ctx context.Context) context.Context {
	return context.WithValue(ctx, cacheContextKey, &cacheContext{
		ctx:  ctx,
		data: make(map[any]map[any]any),
	})
}
```

Then you can use the below 4 methods to read/write/del the data within
the same context.

```go
func GetContextData(ctx context.Context, tp, key any) any
func SetContextData(ctx context.Context, tp, key, value any)
func RemoveContextData(ctx context.Context, tp, key any)
func GetWithContextCache[T any](ctx context.Context, cacheGroupKey string, cacheTargetID any, f func() (T, error)) (T, error)
```

Then let's take a look at how `system.GetString` implement it.

```go
func GetSetting(ctx context.Context, key string) (string, error) {
	return cache.GetWithContextCache(ctx, contextCacheKey, key, func() (string, error) {
		return cache.GetString(genSettingCacheKey(key), func() (string, error) {
			res, err := GetSettingNoCache(ctx, key)
			if err != nil {
				return "", err
			}
			return res.SettingValue, nil
		})
	})
}
```

First, it will check if context data include the setting object with the
key. If not, it will query from the global cache which may be memory or
a Redis cache. If not, it will get the object from the database. In the
end, if the object gets from the global cache or database, it will be
set into the context cache.

An object stored in the context cache will only be destroyed after the
context disappeared.

The only usage of `appVer` was in serviceworker.js, while indeed it
needs the asset version.

This should solve the main problem of dynamic assets getting stale after
a version upgrade. Everything not affected will use query-string based
cache busting, which includes files loaded via HTML or worker scripts.

Introduce a separate .eslintrc in the Vue components folder to
selectively enable vue-eslint-parser there, so that the rest of the
files can use eslint's core parser which can deal with hashbangs.

The fact that the eslint-disable comments worked in HTML was a
unintended side-effect of the files being parsed via vue-eslint-parser,
so I had to disable the parsing of these files in .eslintrc.yaml to make
it work, and finally decided to remove eslint-plugin-html as it causes
more issues than it solves.

* Refactor `i18n` to `locale`

- Currently we're using the `i18n` variable naming for the `locale`
struct. This contains locale's specific information and cannot be used
for general i18n purpose, therefore refactoring it to `locale` makes
more sense.
- Ref: https://github.com/go-gitea/gitea/pull/20096#discussion_r906699200

* Update routers/install/install.go

* ROOT_URL issues: some users did wrong to there app.ini config, then:
    * The assets can not be loaded (AppSubUrl != "" and users try to access http://host:3000/)
    *The ROOT_URL is wrong, then many URLs in Gitea are broken.
Now Gitea show enough information to users.

* JavaScript error issues, there are many users affected by JavaScript errors, some are caused by frontend bugs, some are caused by broken customized templates. If these JS errors can be found at first time, then maintainers do not need to ask about how bug occurs again and again.

* Some people like to modify the `head.tmpl`, so we separate the script part to `head_script.tmpl`, then it's much safer.

* use specialized CSS class "js-global-error", end users still have a chance to hide error messages by customized CSS styles.