DISCLOSURE_TOP_PX, DISCLOSURE_LEFT_PX, and DISCLOSURE_WIDTH_PX
were three hardcoded numbers that drifted the moment anyone touched
the sidebar header layout: SHELL_INSET, header padding, picker row
geometry, or the workspace tile size. Replace them with
WorkspaceDisclosureAnchor::solve(sidebar_width) — a pure function
whose algebra is the geometric inverse of render_sidebar_header,
expressed over named layout constants (HEADER_PT, PICKER_BUTTON_SIZE,
etc.) the renderer already applies.
Picker resize now flows: snapshot → sidebar_width → solve → anchor →
render_workspace_disclosure. Three regression tests lock the default
(66, 98, 180), invariance of left/top under resize, and zero-width
clamp. cargo test ely_app --bin ely_app: 101 passed.
ZacharyZhang-NY
1e85dad291