…om viewport (#8171)

When the tooltip singleton's trigger element has an ancestor with a CSS
`transform` (e.g. `transform3d`), `position: fixed` positions relative
to that ancestor's containing block rather than the viewport. Since
`getBoundingClientRect()` always returns viewport-relative coordinates,
directly using those values as `left`/`top` produces incorrect
positioning.

This PR fixes the issue by first placing the trigger at `(0, 0)`,
reading back the containing block's offset via
`getBoundingClientRect()`, and then subtracting that offset to compute
the correct CSS position.

### Change type

- [x] `bugfix`

### Test plan

1. Embed tldraw inside a container that uses `transform:
translate3d(...)` or similar CSS transform
2. Hover over toolbar buttons and other tooltip-bearing elements
3. Verify tooltips appear correctly positioned next to their target
elements

### Release notes

- Fixed tooltip positioning when tldraw is rendered inside a container
with CSS transforms.

Made with [Cursor](https://cursor.com)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk UI-only change that adjusts how tooltip trigger `left`/`top`
are computed; main risk is minor regressions in edge-case
layout/positioning.
> 
> **Overview**
> Fixes incorrect tooltip placement when `tldraw` is rendered inside a
transformed/offset containing block by adjusting the singleton trigger’s
`position: fixed` coordinates.
> 
> The trigger is now temporarily placed at `(0,0)`, its containing-block
offset is read via `getBoundingClientRect()`, and that offset is
subtracted from the target element’s viewport rect to compute the
correct `left`/`top`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
d384470. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

In order to publish the v4.5.0 release notes and record the v4.4.1
patch, this PR archives release notes and resets `next.mdx` for the next
cycle.

**v4.5.0.mdx** (new file):
- Archived from `next.mdx` with full frontmatter, keywords, and GitHub
release link
- Featured sections: click-through on transparent image pixels (#7942),
breaking `EmbedShapeUtil.configure()` change (#8034)
- API changes: `Editor.getResizeScaleFactor()` (#8042),
`TLImageAsset.pixelRatio` (#8163), `sanitizeSvg` (#7896),
`experimental__onDropOnCanvas` (#7911), enum-to-const refactoring
(#8084)
- 6 improvements and 20 bug fixes from production

**v4.4.0.mdx:**
- Add v4.4.1 patch release section with tooltip positioning fix (#8171)
- Add v4.4.1 to keywords

**next.mdx:**
- Reset with `last_version: v4.5.0` and empty content

### Change type

- [x] `other`

### Code changes

| Section       | LOC change    |
| ------------- | ------------- |
| Documentation | +128 / -107   |

In order to publish the v4.5.0 release notes and record the v4.4.1
patch, this PR archives release notes and resets `next.mdx` for the next
cycle.

**v4.5.0.mdx** (new file):
- Archived from `next.mdx` with full frontmatter, keywords, and GitHub
release link
- Featured sections: click-through on transparent image pixels (#7942),
breaking `EmbedShapeUtil.configure()` change (#8034)
- API changes: `Editor.getResizeScaleFactor()` (#8042),
`TLImageAsset.pixelRatio` (#8163), `sanitizeSvg` (#7896),
`experimental__onDropOnCanvas` (#7911), enum-to-const refactoring
(#8084)
- 6 improvements and 20 bug fixes from production

**v4.4.0.mdx:**
- Add v4.4.1 patch release section with tooltip positioning fix (#8171)
- Add v4.4.1 to keywords

**next.mdx:**
- Reset with `last_version: v4.5.0` and empty content

### Change type

- [x] `other`

### Code changes

| Section       | LOC change    |
| ------------- | ------------- |
| Documentation | +128 / -107   |