feat: sanction DM links and per-event colour coding (#13)

## Summary

- Adds resource links (appeal form, sanction logs, contact page, community invite) to all sanction DMs, separated from the sanction text by a Components v2 separator
- Adds a unique accent colour for every mod log and activity log event type, giving each action a distinct visual identity at a glance

## Changes

- `src/utils/components.ts` — Added `sanctionDmMessage` helper with two-section container (sanction text + links); added full `Colours` palette covering all sanction and activity event types; added `ColourKey` export
- `src/commands/{ban,kick,mute,softban,warn}.ts` — Updated DMs to use `sanctionDmMessage` with the appropriate colour
- `src/modules/logModAction.ts` / `logActivity.ts` — Thread `colour` parameter through to message builders
- All event and command files updated with their respective colours

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #13
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/events/guildMemberUpdate.ts

@@ -41,6 +41,7 @@ export const onGuildMemberUpdate = async(
 
       await logActivity({
         client: newMember.client,
+        colour: "nicknameChange",
         emoji:  "📝",
         fields: [
           `**User**: ${username} (\`${userId}\`)`,
@@ -64,6 +65,7 @@ export const onGuildMemberUpdate = async(
 
       await logActivity({
         client: newMember.client,
+        colour: "rolesAdded",
         emoji:  "➕",
         fields: [
           `**User**: ${username} (\`${userId}\`)`,
@@ -86,6 +88,7 @@ export const onGuildMemberUpdate = async(
 
       await logActivity({
         client: newMember.client,
+        colour: "rolesRemoved",
         emoji:  "➖",
         fields: [
           `**User**: ${username} (\`${userId}\`)`,
@@ -98,6 +101,7 @@ export const onGuildMemberUpdate = async(
     if (oldMember.avatar !== newMember.avatar) {
       await logActivity({
         client: newMember.client,
+        colour: "serverAvatar",
         emoji:  "🖼️",
         fields: [
           `**User**: ${username} (\`${userId}\`)`,