Give each task an assigned colour across the UI; lead links tasks

docs/operations.md

@@ -124,10 +124,12 @@ The Status modal (the navbar's **Status** button; Esc, ×, a click outside it or
 
 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. Activity inside a subagent (`agent.message`, `agent.thinking`, `agent.tool_call`, `agent.tool_result`) carries `payload.parent_tool_use_id`, the ID of the tool call that started the subagent, and never updates `session.context`. `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's **Compact** button shows the latest one as a background fill across the button, proportional to the window, tinted amber from 70% and red from 90%; the exact count is in its tooltip.
 
-Messages byre itself sends an agent (actor `byre`: the restart notice, Sync and Merge prompts, Compact's handoff request) show collapsed like a tool call, labelled `byre` with the first line as the brief; expanding it shows the full text. 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 Claude Code subagent call (the `Agent` or `Task` tool) stands on its own, collapsed, labelled with its `subagent_type` and `description`; expanding it shows the prompt and the call's result. Its summary carries a status from the `agent.vendor` `system` events whose `tool_use_id` names it (`task_started`: running, or running in the background; `task_progress`: its `description`; `task_notification`: its `status`, red unless `completed`). The subagent's own messages, thinking and tool calls (events whose `parent_tool_use_id` names the call) stream inline with the main agent's, in arrival order, each marked `↳ <subagent_type>` with the description as its tooltip; its messages also get an accent rule down their left edge. A run of tool calls groups only calls from the same agent, so a call from another agent starts a new group. A subagent's messages never end the main agent's live message, count as a turn's final message or hide a quiet turn. Claude Code streams a background subagent's activity, but for a foreground one only its prompt, so a foreground subagent shows only as its call, its status and its result. 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 has no `@`-file mentions or path picker: text reaches the agent exactly as typed (stream-json doesn't expand `@path` the way the interactive CLI does), and the agent reads any file the message names with its own tools. 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`: the restart notice, Sync and Merge prompts, Compact's handoff request) show collapsed like a tool call, labelled `byre` with the first line as the brief; expanding it shows the full text. The transcript view has a border in the task's colour (see "Task colours"; the accent in the lead pane) while the session is `running`, and a braille spinner on its last line in the same colour, 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 a coloured 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 Claude Code subagent call (the `Agent` or `Task` tool) stands on its own, collapsed, labelled with its `subagent_type` and `description`; expanding it shows the prompt and the call's result. Its summary carries a status from the `agent.vendor` `system` events whose `tool_use_id` names it (`task_started`: running, or running in the background; `task_progress`: its `description`; `task_notification`: its `status`, red unless `completed`). The subagent's own messages, thinking and tool calls (events whose `parent_tool_use_id` names the call) stream inline with the main agent's, in arrival order, each marked `↳ <subagent_type>` with the description as its tooltip; its messages also get an accent rule down their left edge. A run of tool calls groups only calls from the same agent, so a call from another agent starts a new group. A subagent's messages never end the main agent's live message, count as a turn's final message or hide a quiet turn. Claude Code streams a background subagent's activity, but for a foreground one only its prompt, so a foreground subagent shows only as its call, its status and its result. 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 has no `@`-file mentions or path picker: text reaches the agent exactly as typed (stream-json doesn't expand `@path` the way the interactive CLI does), and the agent reads any file the message names with its own tools. 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 project ▸ task picker at the right end of the right pane's tab strip) lists active tasks with their session state and open inbox item count, and **merge held** on a task with `merge_queued_at`, live while it is open. Tasks with inbox items come first; within each group, the task least recently visited in this browser comes first (never-visited tasks before all others, ties in the server's order: projects by name, tasks newest first). Visit times are kept in the browser's localStorage under `byre.visits`, stamped when a task is selected and again when it is left. After the tasks come the projects, one row each; picking one points the right pane at the project with no task, on the Project tab. Typing filters both and adds a last row that creates a task with the typed text as its title, in the right pane's project (the first project when there is none); Enter picks the highlighted row. Picking a task points the right pane at it on the Transcript tab (see "Lead agent").
 
+**Task colours.** Each task has a colour, `tasks.color` (`color` in the API), an index into the palette of `--task-0` … `--task-N` custom properties at the top of `web/style.css`, one set for light and one for dark, all at least 4.5:1 against the backgrounds so they work as text. `CreateTask` assigns it in the same transaction as the task's row: of the `store.TaskColors` colours, one no active task holds, and among those the one given out longest ago (the lowest `max(rowid)` of tasks with that colour, never-used first), so a new task doesn't take the colour of one just closed. Active tasks have distinct colours until more than `TaskColors` are active at once. `TaskColors` must match the number of palette entries. An element styled with `taskStyle(id)` (`web/src/taskcolor.ts`) sets `--task` for itself and its children from the task's `color`; `--task` defaults to the accent, which is also what a task the page doesn't know gets. The right pane sets it for the selected task, which tints its tab strip, colours the task picker's text, the selected tab's underline, the composer's border and the running border and spinner. Everywhere a task is named it shows in its colour: task titles in the switcher, the Project tab and the Status modal (`.task-name`), and task links (`a.task-link`), including any Markdown link to `#/task/<id>`. The lead's guidance tells it to link every task it names that way, and clicking one points the right pane at the task.
+
 ## Lead agent
 
 Each user has one long-running lead agent, shown in the left pane. It is not tied to a project: it watches every task, tells the human what needs them, points the right pane at it, and acts on the other agents. Its code is `internal/agents/lead.go` (sessions, held input, signals) and `internal/agents/leadtools.go` (its MCP tools).