Team chat commands (!shop, !small, !large, !pos) + join/leave/AFK alerts

[Rathio12]

Summary

Adds team-chat commands, richer presence announcements, automatic Deep Sea tracking, persistent event logs, and a set of anti-spam / reliability fixes. Everything is built to be API-friendly — throttled sends, single/limited replies, no extra polling beyond a gentle background Deep Sea check. See CHANGELOG.md for the full breakdown. Rebased/merged on the current beta tip (includes the teammate-map-markers feature).

New chat commands

• !shop <item> — searches the map's cached vending machines (no extra polling) and replies with the top 3 matches as separate, spaced messages, each grid: item → cost (stock). In-stock first, then cheapest; (+N more) overflow. Junk barter trades (priced in another item) are filtered out when real Scrap prices exist.
• !small / !large — individual Small/Large Oil Rig crate timers (refactored !oilrig into a shared helper).
• !pos <name> — a teammate's current grid (exact-then-partial match).
• !afk — who's AFK and for how long (respects name abbreviation + 128-char limit).

Presence announcements (gated by the existing "Chat Announce" toggle)

• Joined / left, with smart handling of your own team switches (you join someone → announce only you; people join your team → announce each; you leave / team dissolves → suppressed).
• AFK ("X is now AFK for more than 5m") and back from AFK ("X came back from AFK, was AFK for 12m") — announced for any member, including yourself.
• Came online appends offline duration; died appends how long they were alive (e.g. ":skull: X is dead @ G12, was alive for 1h 25m"). Alive/offline clocks survive going offline↔online and are tracked regardless of the announce toggle.
• Multiple announcements are spaced ~2.5s apart.

Deep Sea

• Auto-detected in the background (60s poll on connect) — no need to enable the Shops layer. Skips when full shop polling is active and backs off under API pressure; also keeps the shop cache fresh so !shop works without the layer.
• Direction reported reliably as West (always spawns off the west edge; precise direction isn't readable from the API) and shown in the alert: "Deep Sea event is up (West)".

Persistent event logs (%LOCALAPPDATA%\RustPlusDesk\logs\)

• timeline.log — append-only, crash-safe history of every event (presence, AFK, death, oil rig, cargo, heli, vendor, deep sea).
• events.json — latest state per type (per server, overwritten), loaded on startup to rehydrate the "X ago" timers after a restart. Guards: states from before the server's last wipe (RustMapsWipeTime) or older than ~15h are ignored; past that age commands say "Haven't seen X in a while" instead of a misleading "28h ago".

Anti-spam / reliability

• Global send throttle — min 1.5s gap between any two team-chat sends so bursts don't hammer the API (isolated messages still send instantly).
• Alarm spam cooldown — an alarm firing >3× in a row (each within 2 min) mutes its team-chat + Discord alerts for 10 min (per-alarm); popup/audio still fire.
• Discord webhook forwarding uses a serialized, rate-limited queue honoring Retry-After (was a fresh HttpClient per message with no rate handling).
• Emoji-tolerant delivery confirmation — Rust rewrites :shortcode: emoji to glyphs in its echo, which broke the send-confirm match and caused duplicate re-sends; both sides are normalized now.
• Instant command responses — removed an artificial pre-send delay.

Other

• Configurable AFK threshold (per-server, default 5 min, range 1–60), with a selector in the Chat Commands panel.
• In-game emoji shortcodes on alerts: :skull: (death), :wave: (join/leave), :vending.machine: (shop).
• New strings in Resources.resx + en-US; alert templates editable in the Custom Alerts window.

Builds clean (Release, 0 errors). No changes to existing polling cadence; all additions are opt-in via the chat-commands / chat-announce toggles.