README: new "冷却与半冷却探测（自愈调度）" section with the per-class cooldown
table (5xx exponential to 5min / 401-403 10min / 429 30s fixed / quota aligned
to its window), the probe-slot formula and the ordering rule that probes are
tried last. The LuaJIT section now says the pool is an elastic ceiling rather
than a preallocation and documents both step formulas. Headline figures replaced
with measured ones: idle ~10 MB, ~19 MB starting with a 29 MB audit log, and a
new bullet for on-demand log loading.
package.json also loses a `\u2014` escape and the broken indentation that an
earlier edit left in the electron-builder block.
