feat(cli): add takopi config subcommand (#153)

docs/how-to/projects.md

@@ -11,10 +11,18 @@ takopi init happy-gadgets
 
 This adds a project to your config:
 
-```toml
-[projects.happy-gadgets]
-path = "~/dev/happy-gadgets"
-```
+=== "takopi config"
+
+    ```sh
+    takopi config set projects.happy-gadgets.path "~/dev/happy-gadgets"
+    ```
+
+=== "toml"
+
+    ```toml
+    [projects.happy-gadgets]
+    path = "~/dev/happy-gadgets"
+    ```
 
 ## Target a project from chat
 
@@ -28,30 +36,56 @@ Send:
 
 Projects can override global defaults:
 
-```toml
-[projects.happy-gadgets]
-path = "~/dev/happy-gadgets"
-default_engine = "claude"
-worktrees_dir = ".worktrees"
-worktree_base = "master"
-```
+=== "takopi config"
+
+    ```sh
+    takopi config set projects.happy-gadgets.path "~/dev/happy-gadgets"
+    takopi config set projects.happy-gadgets.default_engine "claude"
+    takopi config set projects.happy-gadgets.worktrees_dir ".worktrees"
+    takopi config set projects.happy-gadgets.worktree_base "master"
+    ```
+
+=== "toml"
+
+    ```toml
+    [projects.happy-gadgets]
+    path = "~/dev/happy-gadgets"
+    default_engine = "claude"
+    worktrees_dir = ".worktrees"
+    worktree_base = "master"
+    ```
 
 If you expect to edit config while Takopi is running, enable hot reload:
 
-```toml
-watch_config = true
-```
+=== "takopi config"
+
+    ```sh
+    takopi config set watch_config true
+    ```
+
+=== "toml"
+
+    ```toml
+    watch_config = true
+    ```
 
 ## Set a default project
 
 If you mostly work in one repo:
 
-```toml
-default_project = "happy-gadgets"
-```
+=== "takopi config"
+
+    ```sh
+    takopi config set default_project "happy-gadgets"
+    ```
+
+=== "toml"
+
+    ```toml
+    default_project = "happy-gadgets"
+    ```
 
 ## Related
 
 - [Context resolution](../reference/context-resolution.md)
 - [Worktrees](worktrees.md)
-