F1: extract the navbar-visibility crux (width/height 0 or right<=0 -> hidden)
from getNavbarRect into a pure isNavbarRectVisible in dock-helpers.ts + 3 tests;
getNavbarRect calls it (identical null cases).
F2: base the dock/undock button's label/icon/title on the effective useDock state
(docked && dockRect present) rather than the raw docked flag, so a docked window
that fell back to floating (collapsed sidebar) doesn't show 'Undock'. Toggle
action unchanged; no remount.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Drag the floating AI-chat window onto the sidebar and release over it to DOCK it
— the window pins to the live navbar rect, overlaying the page tree; a drop-zone
highlight shows while dragging over it. Closing the chat re-shows the tree.
Undock via a header button or by dragging the docked window back onto content
(pops out floating at the drop point). The docked/floating mode persists in
localStorage and the docked window follows the navbar width (manual resize,
space<->shared route change) via a ResizeObserver + sidebar-toggle/transitionend
re-sync; when the navbar is collapsed/absent the window falls back to floating
instead of vanishing. Dock/undock only flips a mode atom + geometry — ChatThread
is never remounted, so an in-flight response stream is not interrupted.
Frontend only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
agent_coder