Initialize repository structure for 200 Solid Edge exercises (Sachidanand Jha)

[Copilot]

Repository was a stub (single-line README). This PR bootstraps it as a fully navigable reference for 200 progressive Solid Edge exercises based on Sachidanand Jha's 3D Modeling Exercises for Engineers and Designers.

Structure

Six category folders, each with a detailed README.md:

Folder	Exercises	Scope
01-Basic-Shapes/	001–040	Extrude, revolve, fillet, shell, holes
02-Intermediate-Parts/	041–090	Brackets, fasteners, jig/fixture components
03-Advanced-Parts/	091–140	Gears, springs, blades, couplings, engine parts
04-Sheet-Metal/	141–160	Flanges, bends, transitions, flat patterns
05-Assembly/	161–180	Mates, mechanisms, gear trains, sub-assemblies
06-Drafting/	181–200	Projections, sections, GD&T, BOM, title block

Root README

• Full 200-exercise index table across all categories
• Repository structure overview
• Getting-started steps (clone → open in Solid Edge)
• File-type reference (.par, .psm, .asm, .dft)
• Contributing guide (branch naming, PR workflow)

.gitignore

Excludes Solid Edge backup/lock files (*.par.bak, *.par.lock, etc.) and OS artefacts; actual model files (.par/.psm/.asm/.dft) are intentionally tracked.

Original prompt

🚀 A comprehensive collection of 200 3D modeling and drafting exercises in Siemens Solid Edge, based on the book by Sachidanand Jha. Includes.