feat: announce on Discourse support forum (#17)

## Summary

- Adds `announceOnDiscourse` module to post announcements to the NHCarrigan Discourse support forum (category 16), tagged by announcement type
- Adds `chunkContent` utility to split long announcements at paragraph/line boundaries for Discord (2000 chars), Reddit (40,000 chars), and Discourse (32,000 chars); Reddit overflows chain as nested replies, Discord as sequential messages, Discourse as sequential replies
- Refactors the announcement route to run all platforms concurrently via `Promise.allSettled`, ensuring a failure on any one platform never blocks the others, with all results reported back
- Fixes generation failure response from incorrect `201` to `500`

✨ This PR was created with love from Hikari~ 🌸

Reviewed-on: #17
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

pnpm-workspace.yaml

@@ -1,3 +1,8 @@
+packages:
+  - bot
+  - client
+  - server
+
 # Security
 
 # Do not execute any scripts of installed packages (project scripts still run)