docs: reflect review fixes (archive default, helper error semantics, TLS warning)
docs(um): use GitHub alerts for the quirks block Splits the old-style blockquote into WARNING (500 quirk), TIP (implicit groups) and NOTE (direction semantics) alerts.
docs: clarify IN/OUT group direction semantics IN and OUT are from the group's point of view: IN = user may send into the group, OUT = user receives its traffic. Adds an explainer to the User Account Management page, rewrites the vague direction param descriptions and fixes the reversed readers/writers examples.
docs: convert blockquote notes/warnings to GitHub alert syntax > **Note:** / > **Warning:** etc. replaced by [!NOTE]/[!WARNING]/ > [!CAUTION] alerts across all API pages; style guide updated to > document the pattern.
docs(user): document implicit group auto-creation/deletion
docs(user): document the complete User Account Management API
Initial wiki docs: Home, Getting Started, Home API, Mission API, User Account Management API