rename .story_kit directory to .storkit and update all references

Renames the config directory and updates 514 references across 42 Rust
source files, plus CLAUDE.md, .gitignore, Makefile, script/release,
and .mcp.json files. All 1205 tests pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.storkit/specs/functional/SLACK_SETUP.md

@@ -0,0 +1,44 @@
+# Slack Integration Setup
+
+## Bot Configuration
+
+Slack integration is configured via `bot.toml` in the project's `.story_kit/` directory:
+
+```toml
+transport = "slack"
+display_name = "Storkit"
+slack_bot_token = "xoxb-..."
+slack_signing_secret = "..."
+slack_channel_ids = ["C01ABCDEF"]
+```
+
+## Slack App Configuration
+
+### Event Subscriptions
+
+1. In your Slack app settings, enable **Event Subscriptions**.
+2. Set the **Request URL** to: `https://<your-host>/webhook/slack`
+3. Subscribe to the `message.channels` and `message.im` bot events.
+
+### Slash Commands
+
+Slash commands provide quick access to pipeline commands without mentioning the bot.
+
+1. In your Slack app settings, go to **Slash Commands**.
+2. Create the following commands, all pointing to the same **Request URL**: `https://<your-host>/webhook/slack/command`
+
+| Command | Description |
+|---------|-------------|
+| `/storkit-status` | Show pipeline status and agent availability |
+| `/storkit-cost` | Show token spend: 24h total, top stories, and breakdown |
+| `/storkit-show` | Display the full text of a work item (e.g. `/storkit-show 42`) |
+| `/storkit-git` | Show git status: branch, changes, ahead/behind |
+| `/storkit-htop` | Show system and agent process dashboard |
+
+All slash command responses are **ephemeral** — only the user who invoked the command sees the response.
+
+### OAuth & Permissions
+
+Required bot token scopes:
+- `chat:write` — send messages
+- `commands` — handle slash commands