refactor(a11y): issues view toggle aria attributes and goal tree expand buttons (#1939)

## Thinking Path

Two interactive UI controls were missing WAI-ARIA attributes, so
screen-reader users couldn't perceive their state. The IssuesList
view-mode toggle already had `title` tooltips but no
`aria-label`/`aria-pressed` and its container had no `role="group"`; the
GoalTree expand/collapse chevron announced only "button". Approach:
attributes only, no logic/render changes, reusing the pattern already
shipped on the Agents page toggle. Per review feedback, GoalTree uses a
**stable** `aria-label` (`` `${goal.title} subtree` ``) with
`aria-expanded` for state, rather than a dynamic label that
double-announces state.

## Issue

_No existing tracking issue — described inline per CONTRIBUTING.md →
"Link Issues or Describe Them In-PR"._

**What happened**
Two components expose buttons with no accessible name or state, making
them unusable via screen reader: (1) the `IssuesList` view-mode toggle
doesn't convey which view is active; (2) the `GoalTree` expand/collapse
chevrons have no name and no expanded/collapsed state.

**Expected behavior**
Both controls announce their purpose and current state to assistive
technology.

**Steps to reproduce**
Enable VoiceOver, open the Issues page and Tab to the view-mode toggle,
then open the Goals page with nested goals and Tab to a tree chevron —
each control announces only "button", with no name and no
pressed/expanded state.

## What Changed

**`ui/src/components/IssuesList.tsx`** — `role="group"` +
`aria-label="View mode"` on the container; `aria-label` ("List
view"/"Board view") and `aria-pressed` on each button.

**`ui/src/components/GoalTree.tsx`** — stable `aria-label` (``
`${goal.title} subtree` ``) and `aria-expanded` on the chevron button.

2 files, ARIA attributes only, no behavioral change.

## Verification

1. Issues page → toggle announces "List view, pressed" / "Board view,
not pressed", grouped as "View mode".
2. Goals page with nested goals → each chevron announces "<goal title>
subtree" with expanded/collapsed state.
3. Manual VoiceOver pass; no visual/behavioral change for sighted users.

## Risks

Minimal — additive HTML attributes with no impact on logic, rendering,
or state. Worst case is a suboptimal announcement string, trivially
adjusted.

## Model Used

Original change human-authored by @bluzername. Two follow-up commits
(stable `aria-label` refinement; removal of a stray tooling file)
applied via maintainer edit; the refinement was drafted with Claude Opus
4.8.

## Checklist

- [x] I searched the GitHub PR list (open + recently closed) for
similar/duplicate PRs before opening — none found.

---------

Co-authored-by: Andrew Aymeloglu <aaymeloglu@gmail.com>

ui/src/components/GoalTree.tsx

@@ -35,6 +35,8 @@ function GoalNode({ goal, children, allGoals, depth, goalLink, onSelect }: GoalN
             e.stopPropagation();
             setExpanded(!expanded);
           }}
+          aria-label={`${goal.title} subtree`}
+          aria-expanded={expanded}
         >
           <ChevronRight
             className={cn("h-3 w-3 transition-transform", expanded && "rotate-90")}

ui/src/components/IssuesList.tsx

@@ -1388,11 +1388,13 @@ export function IssuesList({
 
         <div className="flex items-center gap-0.5 sm:gap-1 shrink-0">
           {/* View mode toggle */}
-          <div className="flex items-center border border-border rounded-md overflow-hidden mr-1">
+          <div className="flex items-center border border-border rounded-md overflow-hidden mr-1" role="group" aria-label="View mode">
             <button
               className={`p-1.5 transition-colors ${viewState.viewMode === "list" ? "bg-accent text-foreground" : "text-muted-foreground hover:text-foreground"}`}
               onClick={() => updateView({ viewMode: "list" })}
               title="List view"
+              aria-label="List view"
+              aria-pressed={viewState.viewMode === "list"}
             >
               <List className="h-3.5 w-3.5" />
             </button>
@@ -1400,6 +1402,8 @@ export function IssuesList({
               className={`p-1.5 transition-colors ${viewState.viewMode === "board" ? "bg-accent text-foreground" : "text-muted-foreground hover:text-foreground"}`}
               onClick={() => updateView({ viewMode: "board" })}
               title="Board view"
+              aria-label="Board view"
+              aria-pressed={viewState.viewMode === "board"}
             >
               <Columns3 className="h-3.5 w-3.5" />
             </button>