Draw the braille spinner as one masked CSS animation

docs/operations.md

@@ -96,7 +96,7 @@ The Admin view (a pane tab, also opened in the right pane by the navbar's **Admi
 
 Agent activity becomes events with `agent_session_id` set: `user.message`, `agent.message`, `agent.thinking`, `agent.tool_call`, `agent.tool_result`, `turn.ended`, `session.state`, `session.model`, and `session.context`. Anything else Claude Code emits (rate-limit status, task progress, state changes) is recorded unchanged as `agent.vendor`. The one exception is partial output: each top-level `text_delta` is broadcast to SSE clients as an `agent.delta` event (`payload.text`, `seq` 0) that is never stored, and the transcript grows a live message from them until the finished `agent.message` replaces it. A `turn.ended` event carries `inbox_item_id` when its final message was filed as a `report` item. `session.context` records the context size whenever it changes: `used` is the last assistant message's input, cache-read, cache-creation and output tokens, and `window` is the model's context window from the turn's `result` (`modelUsage[model].contextWindow`), so it is 0 until the session's first turn after a server start ends. The task header shows the latest one as a percentage of the window, coloured green, amber from 70%, red from 90%.
 
-Messages byre itself sends an agent (actor `byre`, such as the restart notice) show as a muted note, not a user bubble. The transcript view has an accent border while the session is `running`, and a braille spinner on its last line. The spinner is pure CSS: six dots laid out as a braille cell, each switched on and off by its own `step-end` keyframes (`braille-1` to `braille-6` in `web/style.css`) so together they cycle ⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏ every 0.8s. Browsers that freeze animated GIFs (Orion) still run it. Consecutive tool calls (with any thinking between them) collapse into one group whose summary counts calls per tool and file, and file paths show relative to the worktree. A turn's final message that is at least half visible in the transcript while the page is visible dismisses its `report` inbox item, as the viewing user. Selecting a task that has never had a session focuses the composer. In the composer, Enter sends and Shift-Enter adds a newline; unsent text is kept per task in memory, so it survives switching tabs or tasks but not a page reload. The composer is the same whether or not the task has a live session: Send posts to the session's messages, or starts a session with the text when there is none or the last one completed. A sent message shows at once as a "sending…" bubble, replaced by the server's `user.message` event with the same text when it arrives, and removed (text and images back in the composer) if the request fails.
+Messages byre itself sends an agent (actor `byre`, such as the restart notice) show as a muted note, not a user bubble. The transcript view has an accent border while the session is `running`, and a braille spinner on its last line, cycling ⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏ every 0.8s. It is one element with one CSS animation: the ten frames are drawn side by side in an inline SVG used as the `.spinner` mask over an accent background, and the `braille` keyframes in `web/style.css` step the mask position through them. Orion freezes animated GIFs and per-dot `step-end` opacity animations partway through a turn, so it stays a single element with a single animation. Consecutive tool calls (with any thinking between them) collapse into one group whose summary counts calls per tool and file, and file paths show relative to the worktree. A turn's final message that is at least half visible in the transcript while the page is visible dismisses its `report` inbox item, as the viewing user. Selecting a task that has never had a session focuses the composer. In the composer, Enter sends and Shift-Enter adds a newline; unsent text is kept per task in memory, so it survives switching tabs or tasks but not a page reload. The composer is the same whether or not the task has a live session: Send posts to the session's messages, or starts a session with the text when there is none or the last one completed. A sent message shows at once as a "sending…" bubble, replaced by the server's `user.message` event with the same text when it arrives, and removed (text and images back in the composer) if the request fails.
 
 The task switcher (⌘K, or the navbar crumb) lists active tasks with their session state and open inbox item count, live while it is open. Tasks with inbox items come first; otherwise the order is the server's (projects by name, tasks newest first). Typing filters them and adds a last row that creates a task with the typed text as its title, in the current task's project (the first project when no task is selected); Enter picks the highlighted row. Picking a task here or in the Tasks view selects it and, if neither pane shows the Transcript tab, switches a pane that isn't showing Tasks to it.