#26216)

The bundled `/icon/rstudio.svg` rendered the R language logo (gray oval,
blue R), not the RStudio IDE logo, so templates using the `rstudio`
`coder_app` and the bundled URL got the wrong artwork
([#26211](#26211), PRODUCT-383).

This PR:

- Renames the existing `rstudio.svg` (R language logo) to `rproject.svg`
so the artwork stays available for templates that want it.
- Adds a new `rstudio.svg` containing the actual RStudio R-ball logo,
extracted from the [Wikimedia
source](https://upload.wikimedia.org/wikipedia/commons/d/d0/RStudio_logo_flat.svg)
and normalized to `viewBox="0 0 256 256"` to match the rest of the icon
set.
- Adds `rproject.svg` to `site/src/theme/icons.json` so it appears in
the icon picker and gallery alongside `rstudio.svg`.
- Switches the `coder_app "rstudio"` example in
`docs/admin/templates/extending-templates/web-ides.md` to reference
`/icon/rstudio.svg` (and corrects `display_name` to `"RStudio"`),
matching every other example on that page.

| Path | Before | After |
| --- | --- | --- |
| `/icon/rstudio.svg` | R language logo | RStudio R-ball |
| `/icon/rproject.svg` | (did not exist) | R language logo |

<table>
<tr>
<th>Old <code>rstudio.svg</code> &rarr; new
<code>rproject.svg</code></th>
<th>New <code>rstudio.svg</code></th>
</tr>
<tr>
<td align="center"><img
src="https://raw.githubusercontent.com/coder/coder/vigilante/product-383-bundled-iconrstudiosvg-appears-to-show-r-language-logo/site/static/icon/rproject.svg"
width="128" height="128"></td>
<td align="center"><img
src="https://raw.githubusercontent.com/coder/coder/vigilante/product-383-bundled-iconrstudiosvg-appears-to-show-r-language-logo/site/static/icon/rstudio.svg"
width="128" height="128"></td>
</tr>
</table>

**Breaking-change note.** Templates that referenced `/icon/rstudio.svg`
expecting the R language oval will now render the RStudio R-ball.
Templates that want the R language logo should switch to
`/icon/rproject.svg`. The Linear issue acknowledges this tradeoff.

**Client cache caveat.** `site/site.go` serves everything under `/icon/`
with `Cache-Control: public, max-age=31536000, immutable`, so any
browser that already loaded the old artwork at `/icon/rstudio.svg` can
keep displaying it for up to a year before revalidating. A hard refresh
(Ctrl/Cmd+Shift+R) clears it immediately. Cache-busting (hashed icon
URLs) is out of scope for this fix and tracked as a possible follow-up
against PRODUCT-383.

<details>
<summary>Implementation notes</summary>

- Verified geometric fidelity by rendering the new SVG and a
high-resolution crop of the Wikimedia source at 256x256 and computing
the RMS pixel difference: 1.268/255 (~0.5%, essentially antialiasing
noise).
- Picked `viewBox="0 0 256 256"` because 139 of 142 SVGs in
`site/static/icon/` already use that viewBox.
- Searched the repo for `rstudio.svg` references: the only direct one is
`site/src/theme/icons.json`. The docs file references the `rstudio`
`coder_app` slug, not the icon path, so the rename does not break any
callsite.
- R-ball geometry: source circle at (318.7, 312.9) radius 309.8 in the
original `viewBox 0 0 1784.1 625.9`. Translating by (-8.9, -3.1) and
scaling by 256/619.6 maps its bounding box onto `0 0 256 256`. Path
coordinates are pre-computed so the file ships with no transform layer.
- Pre-commit hooks passed locally, including `lint/site-icons`.

</details>

Fixes #26211
Fixes PRODUCT-383

---

_Generated by Coder Agents on behalf of @nickvigilante._

(cherry picked from commit 1dc12f8)