Fixes hyperhive#2893: 'Element.attachShadow: Unable to re-attach to
existing ShadowDOM', crashing swarm.js's live-update render path.
A custom element's connectedCallback fires again on a same-document
*move* (insertBefore/append repositioning an already-connected node
runs the removal + insertion steps for its whole subtree), not just
on a fresh mount. swarm.js's row-fingerprint cache reuses + reorders
existing <li> subtrees on live updates -- reordering an unchanged,
cached row moves its already-initialised <hive-agent-menu>/<hive-menu>
without ever really detaching it from the document, so connectedCallback
re-runs full setup on an instance that's already set up. attachShadow()
throws unconditionally if the host already has a shadow root, and
HiveAgentMenu's unconditional child-menu creation would have appended a
second <hive-menu> on top of the first, doubling the dropdown, once the
shadow-attach crash itself was out of the way.
Both connectedCallbacks now bail early if already initialised
(shadowRoot present / _menu already built). Reproduced the crash and
duplicate-menu bug with an unguarded control copy of both files driven
via headless Chromium (simulating the exact row-reorder move), then
confirmed the guarded version throws nothing, keeps the same shadowRoot
object identity across the move, and doesn't duplicate the dropdown.
<hive-agent-menu> bundled two concerns: the agent-specific trigger/item
list, and generic "click a trigger, get a positioned dropdown" mechanics
(shadow attach, open/close, singleton close-on-open coordination,
outside-click/Escape handling). Pulled the latter out into a new
@hive/shared/hive-menu.js (<hive-menu>), following the established
per-component-directory + ._opts-before-append shadow-DOM pattern
(<hive-dialog>). <hive-agent-menu> now just builds the "⋮" trigger and
the action list and hands them to an internal <hive-menu> instance.
<hive-menu> takes ownership of every <hive-menu> instance in the app for
singleton coordination (closeAllMenus, renamed from closeAllAgentMenus)
— a deliberate widening from the old per-agent-menu-only tracking, since
the mechanism was never agent-specific to begin with.
The one subtlety worth spelling out: <hive-menu> projects the caller's
opaque trigger/content nodes via named <slot>s rather than moving them
into its own shadow root. That's load-bearing, not cosmetic — if it
re-parented them into its own shadow tree instead, <hive-agent-menu>'s
own classes (.agent-menu-btn, .agent-menu-item, ...) would stop applying,
since a <style> only styles elements within the same shadow tree/document
it's part of, and only slotting (not re-parenting) keeps the caller's
nodes in the caller's own tree for styling purposes. That in turn made
<hive-agent-menu>'s own shadow root redundant once it wasn't the thing
positioning or owning open/close state anymore, so it's dropped in favor
of a plain light-DOM element styled by dashboard.css (already the one
page it renders on) — hive-agent-menu.css is gone, its rules folded into
dashboard.css's per-agent-menu section, minus the positioning rules that
moved into hive-menu.css as the new generic `.menu-dropdown` wrapper.
Verified with a standalone esbuild bundle + a cached nix chromium driven
over raw CDP (no puppeteer/playwright/python3 available): hover-reveal
opacity, dropdown open/close/positioning, outside-click/Escape dismissal,
and cross-instance singleton coordination all behave identically to
before the split.
Moves buildAgentMenu's DOM-building body, the menuItem/menuSep/menuLink
helpers, agentMenuPost, and the open-dropdown coordination logic out of
swarm.js and into a new <hive-agent-menu> autonomous custom element
(dashboard/src/agent-menu/), following the same shadow-DOM + one-dir-per-
component shape as hive-dialog. swarm.js's buildAgentMenu is now a thin
wrapper that constructs the element and sets ._opts before appending it,
same convention hive-dialog uses since a custom element created via
document.createElement can't take constructor args.
The module-level "one dropdown open at a time" singleton (previously a
single mutable variable in swarm.js) becomes a tracked Set of open
instances inside the component module; each instance closes itself via
its own close() method rather than another instance reaching into its
shadow internals. The document-level outside-click and Escape listeners
move into the component module too, keyed off e.composedPath() instead of
e.target.closest() -- shadow-DOM event retargeting means a plain
e.target check no longer reliably reaches into a specific instance's
shadow tree. closeAllAgentMenus() is exported for swarm.js's
buildAgentTree, which still needs to close any open menu before it
replaces the container tree DOM.
The hover-reveal opacity rule crosses the shadow boundary via a
--menu-btn-opacity custom property (custom properties inherit through
shadow boundaries): dashboard.css sets it on hover of the light-DOM
hive-agent-menu element, and the component sets it directly from JS while
its own dropdown is open, since that's component-internal state a CSS
selector out in the light DOM can't see. The host element itself takes on
the structural role (flex:none, position:relative, ...) the old
light-DOM .agent-menu wrapper div played, since its shadow tree's
absolute-positioned dropdown needs a positioned ancestor to anchor off of.
Verified end to end with a standalone esbuild-bundled test harness run
under headless chromium: row layout/flex sizing, hover-reveal opacity,
and dropdown positioning all render correctly, and a scripted interaction
pass (singleton exclusivity, outside-click close, Escape close, toggle
behavior, menu-item click close, and the exported closeAllAgentMenus())
all pass.
