feat: updated docs and fixed docker runtime vars injection

- Modified Dockerfile to use placeholder values for frontend environment variables, allowing for runtime substitution.
- Enhanced entrypoint script to apply runtime environment variable configuration, replacing placeholders in JavaScript files with actual values.
- Updated documentation paths in MDX files for Google OAuth images and added detailed setup guides for Discord, Linear, Notion, and Slack OAuth integrations.

surfsense_web/content/docs/connectors/slack.mdx

@@ -3,31 +3,89 @@ title: Slack
 description: Connect your Slack workspace to SurfSense
 ---
 
-# Slack Connector
+# Slack OAuth Integration Setup Guide
 
-Index your Slack conversations and make them searchable.
+This guide walks you through setting up a Slack OAuth integration for SurfSense.
 
-## Prerequisites
+## Step 1: Create a New Slack App
 
-- A Slack workspace
-- Admin permissions to install apps
+1. Navigate to [api.slack.com/apps](https://api.slack.com/apps)
+2. Click **"Create New App"**
+3. Select **"From scratch"** to manually configure your app
 
-## Setup
+![Create an App Dialog](/docs/connectors/slack/slack-create-app.png)
 
-1. Navigate to your Search Space settings
-2. Click on **Add Connector**
-3. Select **Slack** from the list
-4. Authorize SurfSense to access your Slack workspace
-5. Select the channels you want to index
+## Step 2: Name App & Choose Workspace
 
-## What Gets Indexed
+1. Enter **App Name**: `SurfSense`
+2. Select the workspace to develop your app in
+3. Click **"Create App"**
 
-- Public channel messages
-- Private channels (if authorized)
-- Thread replies
-- Shared files and links
+> ⚠️ You won't be able to change the workspace later. The workspace will control the app even if you leave it.
 
-## Sync Frequency
+![Name App & Choose Workspace](/docs/connectors/slack/slack-name-workspace.png)
 
-The Slack connector supports scheduled syncing to keep your conversations indexed.
+## Step 3: Get App Credentials
 
+After creating the app, you'll be taken to the **Basic Information** page. Here you'll find your credentials:
+
+1. Copy your **Client ID**
+2. Copy your **Client Secret** (click Show to reveal)
+
+> ⚠️ Never share your app credentials publicly or include them in code repositories.
+
+![Basic Information - App Credentials](/docs/connectors/slack/slack-app-credentials.png)
+
+## Step 4: Configure Redirect URLs
+
+1. In the left sidebar, click **"OAuth & Permissions"**
+2. Scroll down to **Redirect URLs**
+3. Click **"Add New Redirect URL"**
+4. Enter: `https://localhost:8000/api/v1/auth/slack/connector/callback`
+5. Click **"Add"**, then **"Save URLs"**
+
+![Redirect URLs Configuration](/docs/connectors/slack/slack-redirect-urls.png)
+
+## Step 5: Configure Bot Token Scopes
+
+On the same **OAuth & Permissions** page, scroll to **Scopes** and add the following **Bot Token Scopes**:
+
+| OAuth Scope | Description |
+|-------------|-------------|
+| `channels:history` | View messages and other content in public channels |
+| `channels:read` | View basic information about public channels |
+| `groups:history` | View messages and other content in private channels |
+| `groups:read` | View basic information about private channels |
+| `im:history` | View messages and other content in direct messages |
+| `mpim:history` | View messages and other content in group direct messages |
+| `users:read` | View people in a workspace |
+
+Click **"Add an OAuth Scope"** to add each scope.
+
+![Bot Token Scopes](/docs/connectors/slack/slack-scopes.png)
+
+## Step 6: Enable Public Distribution
+
+1. In the left sidebar, click **"Manage Distribution"**
+2. Under **Share Your App with Other Workspaces**, ensure distribution is enabled
+3. You can use the **"Add to Slack"** button or **Sharable URL** to install the app
+
+![Manage Distribution](/docs/connectors/slack/slack-distribution.png)
+
+---
+
+## Running SurfSense with Slack Connector
+
+Add the Slack environment variables to your Docker run command:
+
+```bash
+docker run -d -p 3000:3000 -p 8000:8000 \
+  -v surfsense-data:/data \
+  # Slack Connector
+  -e SLACK_CLIENT_ID=your_slack_client_id \
+  -e SLACK_CLIENT_SECRET=your_slack_client_secret \
+  -e SLACK_REDIRECT_URI=https://localhost:8000/api/v1/auth/slack/connector/callback \
+  --name surfsense \
+  --restart unless-stopped \
+  ghcr.io/modsetter/surfsense:latest
+```