ci: add lint check to prevent single quotes in bootstrap scripts (#22664)

## Problem

Bootstrap scripts under `provisionersdk/scripts/` are inlined into
templates via `sh -c '${init_script}'`. Any single quote (apostrophe) in
these `.sh` files silently breaks the shell quoting, causing the agent
to never start — with near-invisible error output.

## Changes

- **`scripts/check_bootstrap_quotes.sh`** — new lint script that scans
all `.sh` files under `provisionersdk/scripts/` for single quotes and
fails with a clear error if any are found. Only checks shell scripts
(not `.ps1`, which legitimately uses single quotes).
- **`Makefile`** — added `lint/bootstrap` target wired into the `lint`
dependency list.

Fixes #22062

Makefile

@@ -606,7 +606,7 @@ endif
 # GitHub Actions linters are run in a separate CI job (lint-actions) that only
 # triggers when workflow files change, so we skip them here when CI=true.
 LINT_ACTIONS_TARGETS := $(if $(CI),,lint/actions/actionlint)
-lint: lint/shellcheck lint/go lint/ts lint/examples lint/helm lint/site-icons lint/markdown lint/check-scopes lint/migrations $(LINT_ACTIONS_TARGETS)
+lint: lint/shellcheck lint/go lint/ts lint/examples lint/helm lint/site-icons lint/markdown lint/check-scopes lint/migrations lint/bootstrap $(LINT_ACTIONS_TARGETS)
 .PHONY: lint
 
 lint/site-icons:
@@ -636,6 +636,11 @@ lint/shellcheck: $(SHELL_SRC_FILES)
 	shellcheck --external-sources $(SHELL_SRC_FILES)
 .PHONY: lint/shellcheck
 
+lint/bootstrap:
+	bash scripts/check_bootstrap_quotes.sh
+.PHONY: lint/bootstrap
+
+
 lint/helm:
 	cd helm/
 	make lint