Merge pull request #1 from CHSZLab/kb/034-graph-partitioning-lp-optim…

…ization

Add KB entry: optimizing LP in graph clustering (1.23x)

Seed knowledge base with 30 performance optimization entries (C++ and…

… Python)

Add entries 004-018 covering C++ techniques (SoA/AoS, branchless programming,
SBO, move semantics, constexpr, false sharing, PGO/LTO, mmap, open-addressing
hash maps, SIMD, loop tiling, bit intrinsics, container preallocation, hot-cold
splitting, string_view) and entries 019-033 covering Python techniques (NumPy
vectorization, __slots__, generators, Numba JIT, multiprocessing, dict/set
lookups, mmap, local variable caching, itertools, struct, preallocation,
string join, deque, array module, Cython). Update INDEX.md with all 30 entries.

Add knowledge base banner image and move section before Usage

Re-add resource contention caveat for parallel runs

Add usage note about bypass permissions mode