CDSL Bridge: Mounting Bracket

Use for an L/U/T bracket or a support with a base plus web, lug, tab, or boss.
Invariants: one coherent body, a load path from base to web/boss, datum-driven holes, and no invented fastener assembly.
Plan: base extrude_add_blind -> web/tab/boss add features -> clearance/slot cuts -> holes -> mirror/linear repetition -> late edge treatment.
Use named planar profiles and explicit workplanes. Keep holes after the support geometry so they do not float.
Do not flatten a 3D bracket into a plate or add fillets without a valid selector.