docs(protocol): operating protocol + Charles preferences

Language policy tiers (Go/PHP/C/Java only for our code; Rust tools OK;
python avoid-but-OK in supply chain; node last-resort with consult),
dev-in-docker rule, availability-tracking prohibition.

PREFS-reachableceo.md

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+- Call him reachableceo or Charles. NEVER "the founder" (his words: creepy).
+# Founder preferences (durable)
+- Terse replies (<=5 lines unless detail requested); cite file paths, never restate task/report text.
+- Careful/safe ops on ALL work (founder, 2026-08-28): scripts that mutate
+  anything get preflight checks before mutation, a stated plan, and verify
+  steps after. Idempotent where possible. Confirm gate when interactive.
+- reachableceo has passwordless sudo for ROOT target only; run-as-other-user
+  must route via `sudo runuser -u <user> -- ...` (sudo -u prompts password).
+- Vertical homes are 700; cross-user path tests must run via sudo.
+- Host is Debian 13 (verified 2026-08-28). Never assume distro/paths/commands - verify.
+- Founder wants reachableceo PMO/work stack next (for sudo + Bitwarden work), after crossfeed body of work.
+
+## Availability (2026-08-28 evening)
+- Charles says when he steps away; do NOT track/schedule around his time.
+  No availability windows, no "before you leave" framing, no time-based asks.
+
+## Docs standard (2026-08-28)
+All project docs must be informative, well-formatted, beautiful, and useful. README standard: front matter + Status line, verified quickstart, mermaid architecture, reference tables (CLI/config/routing), honest status table, no dead links. Doc rot found = fix or file follow-up, never leave stale.