* fix: include .astro files in checked project references (#17478)

* fix: implement .astro project-reference fix in astro's own source (#17478)

The previous approach patched @volar/kit via pnpm's patchedDependencies,
which only rewrites node_modules inside this monorepo and never reaches
published npm tarballs. astro check/@astrojs/language-server both build
with tsc -b (no bundling) and depend on @volar/kit as a runtime
dependency, so the patch never shipped to real npm consumers - only the
VS Code extension (which bundles with esbuild) benefited.

Reimplement the fix directly in AstroCheck's checker setup instead.
createTypeScriptChecker's setup callback runs once per project (root and
each reference) and exposes that project's configFileName and mutable
languageServiceHost, which is enough to re-parse each referenced
tsconfig with the language plugins' extraFileExtensions and merge the
result into that project's file list - without touching @volar/kit at
all. getRootFileNames() reads from a separate internal host, so it gets
its own merge on top.

Verified end to end: removed the @volar/kit patch, rebuilt
@astrojs/language-server against the real unpatched dependency, and
confirmed the project-references test suite (including a fileResult
assertion swapped for a direct getRootFileNames() check per review) is
fully green. Also rebuilt astro, @astrojs/markdown-satteri, and the
svelte/vue integrations from a clean state to confirm the two
previously-failing assertions were an artifact of an unbuilt local
environment, not a real pre-existing failure - full suite is 10/10 with
everything built.

* fix(check): rename shadowed variable to fix lint error

* refactor(check): simplify project-reference .astro file handling per review

Per @matthewp: the previous version's dynamic caching/invalidation was
unreliable anyway — it only invalidated by comparing TypeScript's own
file list, which never includes .astro files, so adding/removing only
an .astro file never triggered a re-parse.

Replaces it with a static approach that matches what the root project
already does: each referenced project's tsconfig is parsed once with
extraFileExtensions during checker setup, and the result is merged once
into that project's languageServiceHost.getScriptFileNames() and into
linter.getRootFileNames() — no cache, no resolver callbacks, no
file-list change tracking.

Also removed the editor-language-server claim from the PR description
and changeset — this only fixes AstroCheck; the editor's language server
uses the separate nodeServer.ts/createTypeScriptProject path.

Verified: pnpm --filter @astrojs/language-server build (tsc -b) is clean,
and biome check on check.ts is clean. Could not run the check.test.ts
suite itself locally — it imports packages/astro/test/test-utils.ts,
which needs a full astro package build, and that build fails here on an
unrelated missing workspace dependency (@astrojs/markdown-satteri) not
present in this checkout. Happy to have CI or a maintainer confirm the
existing check.test.ts assertions (file count, error count, and the new
getRootFileNames() .astro-inclusion check) still pass — none of them
test dynamic add/remove behavior, so nothing in that suite should be
sensitive to removing the caching layer.

* chore: reword changeset for end-user impact, not implementation

---------

Co-authored-by: Matthew Phillips <matthewphillips@cloudflare.com>
Co-authored-by: wakqasahmed <training@saerintech.com>

…ailingSlash is 'never' (#17851)

Co-authored-by: factory[bot] <factory[bot]@users.noreply.github.com>

The dev server relied on the file watcher observing the atomic rename
that commits a data store write to invalidate the content virtual
modules. On Windows the watcher can miss that event, leaving dev
serving stale content until a restart (#17335). The store now notifies
listeners after real disk writes and the dev server invalidates
directly, keeping the watcher path as a fallback for other processes
with echo suppression to avoid double reloads.

Co-authored-by: Roman <dev@rman.dev>

…rnings (#17833)

Change `builtPaths` from `Set<string>` to `Map<string, RouteData>` so that
conflict warnings reference the route that actually first rendered the
duplicate pathname, instead of using `matchRoute()` which could return an
unrelated route that merely matches the URL pattern.

Co-authored-by: factory[bot] <factory[bot]@users.noreply.github.com>
Co-authored-by: Matthew Phillips <matthew@matthewphillips.info>
Co-authored-by: Matthew Phillips <matthewphillips@cloudflare.com>

Co-authored-by: Armand Philippot <git@armand.philippot.eu>

Co-authored-by: Florian Lefebvre <contact@florian-lefebvre.dev>

The content layer's image renderer always wrote the srcset attribute,
so an image without responsive candidates produced srcset="", which is
invalid HTML. The older Markdown pipeline in vite-plugin-markdown only
sets the attribute when there are candidates; mirror that here.

…17874)

Rolldown's minifier rewrites string literals as template literals (backticks),
but the regex matching the `@@ASTRO_MANIFEST_REPLACE@@` placeholder only
accepted single and double quotes. Add backtick to the character class in
the manifest and server islands replacement regexes.

Fixes #17843

Co-authored-by: factory[bot] <factory[bot]@users.noreply.github.com>

* fix: cache headers

* Apply suggestion from @matthewp

Co-authored-by:  Matthew Phillips <matthewphillips@cloudflare.com>

* revert change

* update tests

* update tests

---------

Co-authored-by: Matthew Phillips <matthewphillips@cloudflare.com>

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>