docs: add note that project folder must be a Git repository

The `deepwork install` command requires a Git repository but this wasn't
documented, causing confusion for users who try to install in non-Git folders.

Author: weisserj

README.md

@@ -7,12 +7,14 @@ Triage email, give feedback to your team, make tutorials/documentation, QA your
 brew tap unsupervisedcom/deepwork && brew install deepwork
 ```
 
-Then in your project folder:
+Then in your project folder (must be a Git repository):
 ```bash
 deepwork install
 claude
 ```
 
+> **Note:** DeepWork requires a Git repository. If your folder isn't already a repo, run `git init` first.
+
 Now inside claude, define your first job using the `/deepwork_jobs` command. Ex.
 ```
 /deepwork_jobs Make a job for doing competitive research. It will take the URL of the competitor as an input, and should make report including a SWOT analysis for that competitor.
@@ -81,12 +83,14 @@ brew tap unsupervisedcom/deepwork
 brew install deepwork
 ```
 
-Then in any project folder:
+Then in any project folder (must be a Git repository):
 
 ```bash
 deepwork install
 ```
 
+> **Note:** If your folder isn't a Git repo yet, run `git init` first.
+
 **After install, load Claude.** Then verify you see this command: `/deepwork_jobs`
 
 ### 2. Define Your First Workflow