terminal: Allow configuring conda manager (#40577)

Closes #40576
This PR makes Conda activation configurable and transparent by adding a
`terminal.detect_venv.on.conda_manager` setting (`"auto" | "conda" |
"mamba" | "micromamba"`, default `"auto"`), updating Python environment
activation to honor this preference (or the detected manager executable)
and fall back to `conda` when necessary.

The preference is passed via `ZED_CONDA_MANAGER` from the terminal
settings, and the activation command is built accordingly (with proper
quoting for paths). Changes span
`zed/crates/terminal/src/terminal_settings.rs` (new `CondaManager` and
setting), `zed/crates/project/src/terminals.rs` (inject env var),
`zed/crates/languages/src/python.rs` (activation logic), and
`zed/assets/settings/default.json` (document the setting). Default
behavior remains unchanged for most users while enabling explicit
selection of `mamba` or `micromamba`.

Release Notes:
- Added: terminal.detect_venv.on.conda_manager setting to choose the
Conda manager (auto, conda, mamba, micromamba). Default: auto.
- Changed: Python Conda environment activation now respects the
configured manager, otherwise uses the detected environment manager
executable, and falls back to conda.
- Reliability: Activation commands quote manager paths to handle spaces
across platforms.
- Compatibility: No breaking changes; non-Conda environments are
unaffected; remote terminals are supported.

---------

Co-authored-by: Lukas Wirth <me@lukaswirth.dev>
Co-authored-by: Lukas Wirth <lukas@zed.dev>

crates/languages/src/python.rs

@@ -21,9 +21,11 @@ use project::Fs;
 use project::lsp_store::language_server_settings;
 use serde::{Deserialize, Serialize};
 use serde_json::{Value, json};
+use settings::Settings;
 use smol::lock::OnceCell;
 use std::cmp::Ordering;
 use std::env::consts;
+use terminal::terminal_settings::TerminalSettings;
 use util::command::new_smol_command;
 use util::fs::{make_file_executable, remove_matching};
 use util::rel_path::RelPath;
@@ -1171,7 +1173,7 @@ impl ToolchainLister for PythonToolchainProvider {
             .context("Could not convert a venv into a toolchain")
     }
 
-    fn activation_script(&self, toolchain: &Toolchain, shell: ShellKind) -> Vec<String> {
+    fn activation_script(&self, toolchain: &Toolchain, shell: ShellKind, cx: &App) -> Vec<String> {
         let Ok(toolchain) =
             serde_json::from_value::<PythonToolchainData>(toolchain.as_json.clone())
         else {
@@ -1184,10 +1186,34 @@ impl ToolchainLister for PythonToolchainProvider {
 
         match toolchain.environment.kind {
             Some(PythonEnvironmentKind::Conda) => {
+                let settings = TerminalSettings::get_global(cx);
+                let conda_manager = settings
+                    .detect_venv
+                    .as_option()
+                    .map(|venv| venv.conda_manager)
+                    .unwrap_or(settings::CondaManager::Auto);
+
+                let manager = match conda_manager {
+                    settings::CondaManager::Conda => "conda",
+                    settings::CondaManager::Mamba => "mamba",
+                    settings::CondaManager::Micromamba => "micromamba",
+                    settings::CondaManager::Auto => {
+                        // When auto, prefer the detected manager or fall back to conda
+                        toolchain
+                            .environment
+                            .manager
+                            .as_ref()
+                            .and_then(|m| m.executable.file_name())
+                            .and_then(|name| name.to_str())
+                            .filter(|name| matches!(*name, "conda" | "mamba" | "micromamba"))
+                            .unwrap_or("conda")
+                    }
+                };
+
                 if let Some(name) = &toolchain.environment.name {
-                    activation_script.push(format!("conda activate {name}"));
+                    activation_script.push(format!("{manager} activate {name}"));
                 } else {
-                    activation_script.push("conda activate".to_string());
+                    activation_script.push(format!("{manager} activate base"));
                 }
             }
             Some(PythonEnvironmentKind::Venv | PythonEnvironmentKind::VirtualEnv) => {