[feat]: Add pre-message send prevention and restrictions manager

[not-meet]

Summary

Previously, when a user was flagged as a spammer, the system silently stored their spam level in persistence with zero user-facing feedback. Flagged users had no idea they were being monitored or restricted, and could continue sending messages even after being placed on cooldown or suspended.
This PR adds two things:

• Message blocking via IPreMessageSentPrevent restricted users are now actually blocked from sending messages
• User-facing DM notifications flagged users receive a direct message explaining what happened and how long the restriction lasts

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Changes Made

• added checkPreMessageSentPrevent,executePreMessageSentPrevent, checkPostMessageSent in
  AppsSpamMonitorApp.ts - to gate messages from restricted users before they are sent.

• restrictionsManager.ts - handles DMing the flagged user and applying the action based on their spamming level

• en.ts - single source of truth for all runtime notification message strings, keyed by SpammingLevel as typed functions so duration is injected dynamically

• messageUtils.ts - formatDuration (converts ms to human-readable string) and buildMessage

• userStatusStore.ts - added method to fetch if user is restricted or not

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DEMO

• spammers POV of getting pinged by bot when reached a spamming level

Screencast.from.2026-06-06.02-18-55.webm

• messages does not hit rc channel when the spammer is on timeout

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Closes #9