Match split-pane header to design (accent dot + tab title)

The design's split.jsx Pane header leads with an 8 px brand-accent dot,
the lock indicator, host name in INK, then the tab title in INK_4.
The previous header rendered a 24 px brand glyph plus the URL path —
visually heavier and less informative once both panes share most of
their URL prefix.

* brand_glyph: `brand_accent_color(brand)` and `accent_color_for_host`
  collapse each Brand to one design-matching dot color (Figma 7c6cf7,
  Linear 5e6ad2, etc.).
* split_pane: 32 → 30 px header, glyph → 8 px dot, URL path → tab
  title in INK_4. `pane_path_label` deleted; nothing else used it.

cargo test --workspace: 440 passed, 0 failed.

crates/ely_app/src/shell/chrome/mod.rs

@@ -19,7 +19,7 @@ pub(crate) mod typography;
 pub(crate) mod wallpaper;
 
 pub(crate) use appearance_form::render_appearance_form;
-pub(crate) use brand_glyph::render_glyph_for;
+pub(crate) use brand_glyph::{accent_color_for_host, render_glyph_for};
 pub(crate) use command_overlay::render_command_overlay;
 pub(crate) use home::render_home_page;
 pub(crate) use plugin_detail_view::render_plugin_detail_view;
@@ -27,7 +27,7 @@ pub(crate) use settings_layout::render_settings_landing;
 pub(crate) use sidebar::{panel_bg, panel_shadow};
 pub(crate) use sidebar_header::render_sidebar_header;
 pub(crate) use split_pane::{
-    pane_host_label, pane_path_label, pane_url_is_secure, render_compact_split_canvas,
+    pane_host_label, pane_url_is_secure, render_compact_split_canvas,
     render_split_pane_header,
 };
 pub(crate) use topbar::render_topbar;