A11y fixes (#5061)

* Hide decorative icons in LLM actions component from screen readers

The "Open in ChatGPT/Claude" icon links already carry an accessible
name via title/aria-label on the anchor, but the react-icons SVGs
inside them expose role="img" with no name of their own, which axe
flags as a separate unlabeled image. Mark all icons in this component
aria-hidden so the link/button text is the sole accessible name.

* Fix low-contrast checkmark/arrow symbols in dark mode

✔ (U+2714) and ↔ (U+2194) default to Unicode text presentation, so
they fall through this site's font stack to a fallback font that
renders them in a fixed grey regardless of the CSS text color —
unreadable against a dark background.

Swap the permission-table checkmarks for ✅ (U+2705, which defaults
to color-emoji presentation) and force emoji presentation on the
connectivity arrows with the variation selector U+FE0F, matching the
convention already used for ✖️/♻️/▶️ elsewhere in the docs.

* Add before/after screenshots for PR review

Dark-mode crops of the permissions-reference table, same rows and
viewport, showing the checkmark contrast fix. Referenced from the PR
description only — safe to drop before merge.

* cleaning up some extra files

Author: Duncanma

docs/cloud/connectivity/gcp-connectivity.mdx

@@ -133,9 +133,9 @@ This approach is **optional**; Temporal Cloud works without it. It simply stream
 
 | Temporal Cloud setup                       | Use this PHZ domain                | Example                                        |
 | ------------------------------------------ | ---------------------------------- | ---------------------------------------------- |
-| Single-region namespace with mTLS auth     | `<account>.tmprl.cloud`            | `payments.abcde.tmprl.cloud` ↔ `X.X.X.X`       |
-| Single-region namespace with API-key auth  | `<cloud_provider>.api.temporal.io` | `us-central1.gcp.api.temporal.io` ↔ `X.X.X.X`  |
-| Multi-region namespace | `<cloud_provider>.api.temporal.io` | `us-central1.gcp.api.temporal.io` ↔ `X.X.X.X` |
+| Single-region namespace with mTLS auth     | `<account>.tmprl.cloud`            | `payments.abcde.tmprl.cloud` ↔️ `X.X.X.X`       |
+| Single-region namespace with API-key auth  | `<cloud_provider>.api.temporal.io` | `us-central1.gcp.api.temporal.io` ↔️ `X.X.X.X`  |
+| Multi-region namespace | `<cloud_provider>.api.temporal.io` | `us-central1.gcp.api.temporal.io` ↔️ `X.X.X.X` |
 
 ### Step-by-step instructions