## Refined Implementation Plan: Fix Poll Option Unresponsiveness on Android/Chrome

### Objective  
Resolve the hit-test dead zone caused by the absolutely positioned `.poll-option-bar` inside a `position: relative; overflow: hidden` `<button>`, and provide immediate visual feedback to the user on touch.

### Changes Required

#### 1. `engagement.css` – Remove Absolute Child from Button

**Problem:** `.poll-option` is a `<button>` with `position: relative; overflow: hidden`. Its child `.poll-option-bar` uses `position: absolute; inset: 0`. On Chrome Android, this combination creates a layer that absorbs touch events even with `pointer-events: none`.

**Fix:** Replace the `<div>` bar with a `::before` pseudo-element on `.poll-option` that does not interfere with hit-testing. The bar width will be controlled via a CSS custom property `--vote-percent` set by JavaScript.

- Locate `.poll-option-bar` (approx. line 174) and its parent `.poll-option`.
- **Remove** the `.poll-option-bar` rule entirely.
- **Update** `.poll-option`:
  - Keep `position: relative; overflow: hidden;` (required for the pseudo‑element clip).
  - Add `::before` for the visual bar:
    ```css
    .poll-option::before {
      content: '';
      position: absolute;
      top: 0; left: 0;
      height: 100%;
      width: var(--vote-percent, 0%);
      background: <current-bar-color>; /* copy the existing background value */
      pointer-events: none;           /* critical – ensures clicks pass through */
    }
    ```
- Ensure `pointer-events: none` is on the pseudo-element (it is inherited, but explicit is clearer).
- If `.poll-option-bar` had additional styles (e.g., border-radius, transitions), apply them to `::before`.

#### 2. `PollManager.js` – Optimistic UI Feedback + Bar Width via CSS Variable

- **In the `onClick` handler**, when a vote is initiated (the branch that calls `this.vote(option)`), immediately add a CSS class (e.g., `poll-option--voting`) to the clicked `target.closest('.poll-option')`. This provides instant visual feedback before the async fetch completes.
- **Remove that class** after the fetch resolves (both success and failure), so the button returns to its default state.
- **Update bar rendering:** Instead of directly manipulating an inner `.poll-option-bar` element, set the CSS custom property `--vote-percent` on the `.poll-option` element after the vote succeeds. For example:  
  ```javascript
  optionElement.style.setProperty('--vote-percent', `${percentage}%`);
  ```
- **No change** to event type (still `pointerdown`) – the hit-test fix is sufficient. No `preventDefault()` is removed because it is not called in the vote path (as confirmed by the investigation).

#### 3. `engagement.css` – (Optional) Add `poll-option--voting` Style

Define a quick visual change to reassure the user:
```css
.poll-option--voting {
  background-color: rgba(0,0,0,0.05); /* subtle darkening */
  transition: background-color 0s;     /* instant, no delay */
}
```

### Files to Modify (Summary)
- `engagement.css` – Replace `.poll-option-bar` with `::before` pseudo-element; add `--voting` class style.
- `PollManager.js` – Add optimistic class toggle; update bar-width setter to use CSS variable.

### Verification Steps (Definition of Done)
- [ ] Run `pip install -e '.[dev]' -q && make test-unit` – all unit tests pass (including existing poll API tests).
- [ ] Run `pip install -q ruff && ruff check .` – no new lint errors (pre‑existing `F401` in `routers/messages.py` is acceptable).
- [ ] Manual verification on an Android device or emulator with Chrome:
  - Open a page containing a poll.
  - Tap a poll option – a subtle background change should appear instantly.
  - After a short delay, the bar updates to reflect the vote.
  - Tapping the center of the option (where the old bar used to be) must trigger the vote every time.
- [ ] Confirm desktop behaviour is unchanged (the pseudo‑element renders identically in non‑mobile browsers).

### Rollback
Revert the two files. The pseudo‑element approach is backward‑compatible with existing browsers and does not alter any other functionality.