add nushell terminal and completion support (#8628)

Signed-off-by: Can H. Tartanoglu <gpg@rotas.mozmail.com>

documentation/docs/guides/goose-cli-commands.md

@@ -104,7 +104,7 @@ Once installed, you can:
 - Discover options without checking `--help`
 
 **Arguments:**
-- **`<SHELL>`**: The shell to generate completions for. Supported shells: `bash`, `elvish`, `fish`, `powershell`, `zsh`
+- **`<SHELL>`**: The shell to generate completions for. Supported shells: `bash`, `elvish`, `fish`, `nu`, `powershell`, `zsh`
 
 **Usage:**
 ```bash
@@ -112,6 +112,7 @@ Once installed, you can:
 goose completion bash
 goose completion zsh
 goose completion fish
+goose completion nu
 ```
 
 **Installation by Shell:**
@@ -153,6 +154,20 @@ goose completion fish > ~/.config/fish/completions/goose.fish
 
 Then restart your terminal or run `exec fish`.
 
+</TabItem>
+<TabItem value="nu" label="Nushell">
+
+```nu
+let autoload_dir = ($nu.user-autoload-dirs | first)
+mkdir $autoload_dir
+goose completion nu | save --force ($autoload_dir | path join "goose.nu")
+```
+
+Then restart Nushell or run:
+```nu
+source (($nu.user-autoload-dirs | first) | path join "goose.nu")
+```
+
 </TabItem>
 <TabItem value="powershell" label="PowerShell">
 

documentation/docs/guides/terminal-integration.md

@@ -31,6 +31,16 @@ Add to `~/.config/fish/config.fish`:
 goose term init fish | source
 ```
 
+</TabItem>
+<TabItem value="nu" label="Nushell">
+
+Add to `~/.config/nushell/config.nu`:
+```nu
+let goose_term_init = ($nu.cache-dir | path join "goose-term-init.nu")
+^goose term init nu | save --force $goose_term_init
+source $goose_term_init
+```
+
 </TabItem>
 <TabItem value="powershell" label="PowerShell">
 
@@ -87,6 +97,15 @@ eval "$(goose term init bash --name my-project)"
 goose term init fish --name my-project | source
 ```
 
+</TabItem>
+<TabItem value="nu" label="Nushell">
+
+```nu
+let goose_term_init = ($nu.cache-dir | path join "goose-term-init.nu")
+^goose term init nu --name my-project | save --force $goose_term_init
+source $goose_term_init
+```
+
 </TabItem>
 <TabItem value="powershell" label="PowerShell">
 
@@ -110,6 +129,36 @@ eval "$(goose term init zsh --name auth-bug)"
 # Continues the same conversation with context
 ```
 
+## Default Handler
+
+Use `--default` if you want goose to answer commands your shell cannot resolve.
+
+<Tabs groupId="default-shells">
+<TabItem value="zsh" label="zsh" default>
+
+```bash
+eval "$(goose term init zsh --default)"
+```
+
+</TabItem>
+<TabItem value="bash" label="bash">
+
+```bash
+eval "$(goose term init bash --default)"
+```
+
+</TabItem>
+<TabItem value="nu" label="Nushell">
+
+```nu
+let goose_term_init = ($nu.cache-dir | path join "goose-term-init.nu")
+^goose term init nu --default | save --force $goose_term_init
+source $goose_term_init
+```
+
+</TabItem>
+</Tabs>
+
 ## Show Context Status in Your Prompt
 
 Add `goose term info` to your prompt to see how much context you've used and which model is active during a terminal goose session. 
@@ -138,6 +187,13 @@ function fish_prompt
 end
 ```
 
+</TabItem>
+<TabItem value="nu" label="Nushell">
+
+```nu
+$env.PROMPT_COMMAND = {|| $"(goose term info) (pwd)> " }
+```
+
 </TabItem>
 <TabItem value="powershell" label="PowerShell">
 
@@ -170,6 +226,11 @@ You can also check the id of the goose session in your current terminal:
 echo $AGENT_SESSION_ID
 # Should show something like: 20251209_151730
 ```
+```nu
+# Nushell
+$env.AGENT_SESSION_ID
+# Should show something like: 20251209_151730
+```
 To share context across terminal windows, use a [named session](#named-sessions) instead.
 
 **Session getting too full** (prompt shows `●●●●●`):
@@ -178,3 +239,9 @@ If goose's responses are getting slow or hitting context limits, start a fresh g
 # Start a new goose session in the same shell
 eval "$(goose term init zsh)"
 ```
+```nu
+# Nushell
+let goose_term_init = ($nu.cache-dir | path join "goose-term-init.nu")
+^goose term init nu | save --force $goose_term_init
+source $goose_term_init
+```