feat: add slash commands and context menu command (#16)

## Summary

This PR adds a suite of slash commands and a context menu command to Amari, along with shared utilities and quality improvements across the board.

### New Commands
- **`/create-issue`** — generates a GitHub issue on a specified repo using AI-drafted content (title, description, acceptance criteria)
- **`/create-task`** — creates a task in Naomi's Leantime instance with an AI-drafted description and configurable priority
- **`/onboard-mentee`** — automates the mentorship onboarding flow (GitHub invite, forum thread, role assignment)
- **Forward to Owner** (context menu, message command) — forwards any message to Naomi with action buttons (contributed by @teklu)

### Shared Utilities
- **`src/utils/makeAiRequest.ts`** — a single wrapper around the Anthropic SDK for all AI calls, with Amari's personality prompt baked in and full error handling
- **`src/events/handleInteractionCreate.ts`** — extracted interaction handler (was inline in `index.ts`) to keep complexity under control

### Quality Improvements
- `ephemeral: true` → `flags: [ MessageFlags.Ephemeral ]` (deprecated API removed)
- Full `try/catch` + `logger.error` audit across all modules (`logMenteeJoin`, `checkAchievements`, `processMentorshipRole`, `processGitHubEvent`)
- `deployGlobal.ts` replaced with a static `commands.json` payload for manual registration
- Amari's personality prompt updated to reflect her actual character — warm, observant, and relentlessly caring

### Notes
- `CLIENT_ID` is needed in 1Password at `op://Environment Variables - Naomi/Amari/client id` for the `commands.json` registration call
- The forward-to-owner command (PR #13, contributed by @teklu) is fully preserved with original commit authorship

✨ This PR was created with help from Hikari~ 🌸

Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-authored-by: Teklu <tekluabayneh@gmail.com>
Reviewed-on: #16
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/commands/forwardToOwner.ts

@@ -0,0 +1,62 @@
+/**
+ * @copyright NHCarrigan
+ * @license Naomi's Public License
+ * @author Teklu Abayneh
+ */
+
+import {
+  DiscordAPIError,
+  MessageFlags,
+  type MessageContextMenuCommandInteraction,
+} from "discord.js";
+import { ids } from "../config/ids.js";
+import { getComponentsForNaomi } from "../utils/getComponentsForNaomi.js";
+import { logger } from "../utils/logger.js";
+
+/**
+ * Forwards a message to Naomi via DM using a context menu command.
+ * @param interaction -- The message context menu interaction.
+ */
+const forwardToOwner = async(
+  interaction: MessageContextMenuCommandInteraction,
+): Promise<void> => {
+  await interaction.deferReply({ flags: [ MessageFlags.Ephemeral ] });
+
+  if (interaction.user.id !== ids.users.naomi) {
+    await interaction.editReply("❌ Only Naomi can use this command.");
+    return;
+  }
+
+  const message = interaction.targetMessage;
+  if (message.author.id === ids.users.naomi) {
+    await interaction.editReply(
+      "No need to forward your own message to yourself 😄",
+    );
+    return;
+  }
+
+  try {
+    const naomi = await interaction.client.users.fetch(ids.users.naomi);
+    await naomi.send({
+      components: getComponentsForNaomi(
+        message.author,
+        message.content,
+        message.url,
+      ),
+      flags: [ MessageFlags.IsComponentsV2 ],
+    });
+    await logger.metric("forwarded_message", 1, { user: message.author.id });
+    await interaction.editReply({ content: "✅ Forwarded to your DMs!" });
+  } catch (error) {
+    let replyText = "❌ Failed to forward message.";
+    if (error instanceof DiscordAPIError && error.code === 50_007) {
+      replyText = `${replyText} (Naomi's DMs might be closed)`;
+    }
+    if (error instanceof Error) {
+      await logger.error("forwardToOwner command", error);
+    }
+    await interaction.editReply(replyText);
+  }
+};
+
+export { forwardToOwner };