docs: scrub internal/operational info from public docs

Remove deploy-infra + dev-session leakage: the modsharp-deploy gamedata-nesting
gotcha, the internal test-plan section (server name, removed sp_setpc/sp_sendfake
commands, SUBST-* diagnostic tags), absolute /home paths, internal capture-log
paths (cs2-bins/re-dumps), and 'morning/overnight session' framing. Keeps the RE
substance + public install steps.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>