feat(ui): project detail, task drawer and Kanban board (M4)

[gdarko]

Slice 2 of the module's UI (M4): the project detail page, the task drawer, the
task list and the Kanban board. Based on feat/ui-projects, which carries the
projects index this builds on.

What is here

Project detail projects/:id, with Overview, Tasks, Time and Members
rendered through <router-view> as registered children. The header shows the
name, identifier, status badge, the customer name looked up through the host
contact endpoint (falling back to #id), Edit through the existing project
modal and Archive/Restore. Overview renders the task counts, logged and
billable minutes, billable and unbilled amounts and a budget bar when the
project has one.

Board board, filtered by project and assignee, every column in one
request. Cards carry the name, number, project identifier, priority, assignee
initials, due date (red when overdue) and the billable flag. Drag uses
sortablejs directly; a "New task" button per column opens the drawer preset to
that column, and clicking a card opens it for editing.

Task drawer, shared by the board and every list: name, description,
project, read-only customer, status, assignee, priority, due date, estimate in
hours, billable and a rate override in major units, plus delete with a
confirm. Hours become minutes and major units become minor units on the way
out, and a 422 renders under its field.

Task list, a server-side BaseTable over the tasks endpoint, used by the
project Tasks tab and by an all-tasks page at tasks.

The projects index rows now link to the detail page and its header links to
the board.

Notes

• A drop is undone in the DOM before the model changes, so Vue stays the only
  writer of the card's position. The neighbours in the target column become
  the before_id and after_id the move endpoint orders by, the returned
  board_position is applied, and a failed move puts both columns back with a
  notification.
• Resolving the detail route by name matches the parent record alone, so the
  page settles on its Overview child when it is the target itself. Without
  that, a link straight to the project would render an empty body.
• Only GET projects/{id} carries the totals, so every write on the detail
  page re-reads the project rather than keeping what the write returned.
• New registrations, messages, api functions and types live in new files
  (registrations/board.ts, messages/board.ts, api/board.ts,
  types/task.ts, types/task-status.ts, types/board.ts,
  types/project-member.ts, types/time-entry.ts), so init.ts gains one
  import and one call and messages.ts is untouched. api.ts exports its
  base path, and support/format.ts gains three helpers at the end.
• sortablejs is a runtime dependency bundled into dist/; it has no Vue
  dependency of its own. dist/init.js still destructures the host's Vue
  exactly once and imports nothing from "vue".

Checks

pnpm run lint, pnpm exec tsc --noEmit, pnpm run build,
validate-module and validate-package all pass, and dist/ is committed.

Driven in the running app: the projects index, the detail heading and its four
tabs, a task created through the drawer, a card dragged between columns and
reordered inside one (both persisted across a reload), attaching and detaching
a project member, archive and restore, and the all-tasks page. No console
errors.

https://claude.ai/code/session_01DCf36XDKprZifej8dc2r1E

[gdarko]

Superseded by #14, which carries this stack consolidated into three commits on top of main.