feat(install): add SENTRY_INIT env var to run wizard after install

Lets users install the CLI and launch the setup wizard in one command:

    SENTRY_INIT=1 curl -fsSL https://cli.sentry.dev/install | bash

Uses </dev/tty to reopen stdin from the terminal since curl | bash
consumes it for the pipe.

Also adds `install` to the docs-preview workflow path filter so changes
to the install script trigger a preview build.

Closes #682

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: betegon

.github/workflows/docs-preview.yml

@@ -4,6 +4,7 @@ on:
   pull_request:
     paths:
       - 'docs/**'
+      - 'install'
       - '.github/workflows/docs-preview.yml'
 
 permissions:

install

@@ -89,11 +89,13 @@ Options:
 Environment Variables:
     SENTRY_INSTALL_DIR      Override the installation directory
     SENTRY_VERSION          Install a specific version (e.g., 0.19.0, nightly)
+    SENTRY_INIT             Set to 1 to run \`sentry init\` after installing
 
 Examples:
     curl -fsSL https://cli.sentry.dev/install | bash
     curl -fsSL https://cli.sentry.dev/install | bash -s -- --version nightly
     curl -fsSL https://cli.sentry.dev/install | bash -s -- --version 0.19.0
+    SENTRY_INIT=1 curl -fsSL https://cli.sentry.dev/install | bash
     SENTRY_VERSION=nightly curl -fsSL https://cli.sentry.dev/install | bash
     SENTRY_INSTALL_DIR=~/.local/bin curl -fsSL https://cli.sentry.dev/install | bash
 EOF
@@ -276,3 +278,9 @@ trap - EXIT
 
 # shellcheck disable=SC2086
 "$tmp_binary" cli setup $setup_args
+
+# Optionally launch the setup wizard after install.
+# </dev/tty reopens stdin from the terminal since `curl | bash` consumes it.
+if [[ "${SENTRY_INIT:-}" == "1" ]]; then
+  sentry init </dev/tty
+fi