Craft Input Bar Redesign

Redesign of the Craft chat composer:

1. Entry chips above the textarea. Active skills and apps render as removable chips in a strip above the input (alongside file attachments) instead of inline tiles inside the contentEditable.
2. + menu. The paperclip is replaced by a + button that opens downward with a Files action plus Skills and Apps flyout panels (open to the right on hover, Anthropic-style).
3. BaseInputBar abstraction. The shell shared by Craft and the main app chat is extracted into a slot-based component so each surface only supplies what's unique to it.
4. Drag-and-drop. Files dropped anywhere in the chat panel upload (react-dropzone, mirroring the main app).

Components

Component	Path	Responsibility
BaseInputBar	web/src/sections/input/BaseInputBar.tsx	Shared shell: container, contentEditable textarea (useContentEditable), submit/queue/interrupt logic, paste-tile popover. Exposes slots topSlot / bottomLeftSlot / bottomRightSlot, extension hooks (onPasteText, onPasteFiles, onInputCallback, onSelectionChange), and an imperative handle (focus, setMessage, getTextBeforeCursor, getCaretRect, deleteBeforeToken).
InputChipStrip	web/src/sections/input/InputChipStrip.tsx	Single flush-left row of chips (skills/apps lead, files follow), all using one InputChip primitive. Animates height on first/last chip and chip enter/exit (respects prefers-reduced-motion).
PlusMenuButton	web/src/sections/input/PlusMenuButton.tsx	Domain-agnostic + popover: a generic items array of action rows (onSelect) and flyout rows (flyoutItems), null entries as dividers. Flyouts open to the right on hover.
EntryPickerPopover / EntryInfoPopover	web/src/sections/input/	The / picker (Skills + Apps sections) and the read-only info popover shown when a chip is clicked.
CraftInputBar	web/src/app/craft/components/CraftInputBar.tsx	Composes BaseInputBar. Owns activeEntries state; wires useSlashPicker and buildEntryMenuItems.
useSlashPicker	web/src/hooks/useSlashPicker.ts	Drives the /-triggered picker (session/anchor + input/selection/select handlers) over a BaseInputBar, surfacing the chosen PickerEntry.
buildEntryMenuItems	web/src/app/craft/components/buildEntryMenuItems.tsx	Pure mapping of picker sections → PlusMenuItem[].

Entry selection flow

Selecting an entry via the / picker or the + menu appends it to CraftInputBar's activeEntries (deduped by slug) — no inline DOM tile is created. On submit, active entries are serialized as /<slug> prefixes on the message, then cleared. Clicking a chip opens the read-only EntryInfoPopover.

Scope

• Only Craft is affected. The main-app composer (web/src/sections/input/AppInputBar.tsx) is untouched.
• BaseInputBar's three slots (topSlot = files row, bottomLeftSlot = left controls, bottomRightSlot = mic) cover AppInputBar's layout, so migrating it onto BaseInputBar (voice, deep research, multi-model, tab reading) is a follow-up PR.