feat: replace create-task and create-issue with unified create-ticket (#18)

## Summary

- Removes `/create-task` (LeanTime) and `/create-issue` (Gitea) slash commands
- Introduces `/create-ticket` with a `platform` choice argument: **LeanTime**, **Asana**, **Gitea**, **GitHub**
- User provides only a `description`; the AI generates both the title and a fleshed-out body
- `owner` and `repo` arguments are optional but validated at runtime when Gitea or GitHub is selected
- Adds `ASANA_KEY` to `prod.env` (1Password reference — key needs to be added to vault)
- Command remains restricted to Naomi's user ID

## Test plan

- [ ] Register updated `commands.json` against the Discord API
- [ ] Add `ASANA_KEY` to 1Password vault at `op://Environment Variables - Naomi/Amari/asana key`
- [ ] Test `/create-ticket platform:LeanTime description:...` creates a task on the LeanTime board
- [ ] Test `/create-ticket platform:Asana description:...` creates a task in Naomi's Asana project
- [ ] Test `/create-ticket platform:Gitea owner:nhcarrigan repo:amari description:...` creates a Gitea issue
- [ ] Test `/create-ticket platform:GitHub owner:naomi-lgbt repo:... description:...` creates a GitHub issue
- [ ] Test that omitting `owner`/`repo` for Gitea/GitHub returns a helpful error
- [ ] Verify AI generates a sensible title and description from the raw description

✨ This issue was created with help from Hikari~ 🌸

Reviewed-on: #18
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

prod.env

@@ -9,4 +9,5 @@ BASEROW_TOKEN="op://Environment Variables - Naomi/Amari/baserow token"
 RA_KEY="op://Environment Variables - Naomi/Amari/retroachievements key"
 LEANTIME_KEY="op://Environment Variables - Naomi/Amari/leantime key"
 GITEA_KEY="op://Environment Variables - Naomi/Amari/gitea key"
+ASANA_KEY="op://Environment Variables - Naomi/Amari/asana key"
 ANTHROPIC_KEY="op://Environment Variables - Naomi/Hikari/anthropic_key"