#1509: Timeline effect rows show the effect's colour label

Problem: effect colour labels (26.5) were drawn only on the Effect Controls header; the Timeline's effect rows looked unlabelled.

Fix: an effect group row in the Timeline paints the label colour as a 4 px bar on its left edge (same look as the Effect Controls header) and registers `timeline.group.<uid>.label` with the label's name for agents. Docs: gaps.md row 21 and ui-parity.md updated.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docs/gaps.md

@@ -77,7 +77,7 @@ are grouped by area; the issue tracker has the rest.
 | 18 | **Relative paths and relinking** | Projects store absolute footage paths; no relink when a project moves | Moving or sharing a project breaks it | 6–12 h | G4 · [file-format-parity.md](file-format-parity.md) |
 | 19 | **Plug-in ecosystem** | No After Effects SDK hosting (#600, #327 OpenFX, #334, #376 plug-in manager); our WebAssembly API has no third-party plug-ins | Many pro projects depend on Trapcode, Element, Saber… | 40–80 h for API growth; SDK hosting needs an owner decision | G8 · [scripting-parity.md](scripting-parity.md) |
 | 20 | **Multi-monitor and video output** | #486: any panel can move into a native window of its own (panel menu ▸ Move Panel to New Window, `window.panelWindow`) and so onto another screen, restored with the workspace; still missing: dragging tabs between those windows, app shortcuts while one has the focus, named workspaces remembering them, Mercury Transmit to video hardware (we have a second preview window only) | Two-screen setups are standard for professionals | 10–20 h | G2 · [hardware-parity.md](hardware-parity.md) |
-| 21 | **Small 26.x features** | Proportional Scrubbing (26.2), pasting Illustrator's own clipboard data as shapes (26.3; SVG markup on the clipboard pastes as a shape layer, #738), variable-font filter (26.3), the rebuilt Effect Controls (26.5). Percentage guides (View ▸ Add Percentage Guide, Convert Guides to Percentage / Pixels) and effect colour labels (Effect Controls header bar and right-click Label menu, `effect.setLabel`) are in (#1095), built from the release notes' one-line descriptions and never compared with After Effects: the Timeline shows no effect label, and the labels' exact UI there is unknown | Users of the current version expect them | 10–20 h left | — · [ui-parity.md](ui-parity.md) |
+| 21 | **Small 26.x features** | Proportional Scrubbing (26.2), pasting Illustrator's own clipboard data as shapes (26.3; SVG markup on the clipboard pastes as a shape layer, #738), variable-font filter (26.3), the rebuilt Effect Controls (26.5). Percentage guides (View ▸ Add Percentage Guide, Convert Guides to Percentage / Pixels) and effect colour labels (Effect Controls header bar and right-click Label menu, `effect.setLabel`) are in (#1095), built from the release notes' one-line descriptions and never compared with After Effects: the Timeline's effect rows wear the label as a colour bar on the left edge (#1509), but After Effects' exact UI there is unknown | Users of the current version expect them | 10–20 h left | — · [ui-parity.md](ui-parity.md) |
 | 22 | **Encoder efficiency** | HEVC / AV1 have no B-frames, multi-reference or SAO / CDEF; Opus no FEC / DTX; single-file intermediates are 8-bit uncompressed QuickTime only (#372 closed by #778: no 16-bpc, AVI or lossless-compressed codec); #325 render over existing file | Larger files than After Effects + Media Encoder | 20–40 h | G6 · [file-format-parity.md](file-format-parity.md) |
 | 23 | **Essential Graphics interchange** | Templates are `.ectemplate`, not `.mogrt`; #338 and #611 closed | Premiere editors can't use our templates | 15–30 h | — · [file-format-parity.md](file-format-parity.md) |
 | 24 | **Timeline depth requests** | #601 expand precomps in place, #602 reorderable render stack, #604 guide-only effects, #425 keyframe confusion (#355 and #428 closed) | Power-user speed | 15–30 h | G2 · [ui-parity.md](ui-parity.md) |