Refresh stale index overwrite chrome for new SourceBrowser

[tannergooding]

The src/index/overwrite/ files were authored against the pre-#264 SourceBrowser and are copied over the freshly generated index at build time (index.proj BuildIndex), so they shadow the new chrome both in the locally-served static files and in the copies uploaded to blob storage. After #264 deployed the new SourceBrowser, source.dot.net kept serving the old styles.css (28,429 B vs the new 45,108 B), old header.html/overview.html, and the empty SolutionExplorer.html placeholder in place of the real tree -- which is why the site looked broken while https://source.terrafx.dev (running the un-overwritten chrome) rendered correctly.

Every broken asset matched the checked-in overwrite byte-for-byte, and all were freshly re-uploaded to blob on the last run, so this was stale build input rather than a CDN/caching issue.

---

• Delete overwrite/wwwroot/styles.css -- a stale copy (only ever relocated, never customized); the new base styles.css is now used.
• Delete overwrite/index/overview.html -- the new base is already .NET-branded, feature-complete, and gets $(IndexRunDate)/$(ProjectCount)/$(AssemblyCount)/$(SourceBrowserVersion) stamped by HtmlGenerator.
• Delete overwrite/index/SolutionExplorer.html -- the empty override from Override the solution explorer with an empty one #18 is no longer wanted now that the Solution Explorer supports repo filtering; the generated tree is served instead.
• Refresh overwrite/index/header.html onto the new base, restoring the meta charset/viewport tags and the mobile paneToggle, while keeping the .NET Source Browser branding.

Web.config and AffiliateLinks.txt are unchanged (the latter is still consumed by SourceIndexServer).

Note: header.html remains the one drift-prone override -- a future base header change will silently re-break it, which is exactly this bug's failure mode. Longer term the .NET Source Browser branding would be better carried in the SourceBrowser base so no overwrite is needed.

[tannergooding]

@akoeplinger, @jeffhandley. The change otherwise went through and is working, but it turns out source-indexer has a custom step (outside the sourcebrowser folder) which was overwriting a few of the files with custom ones incompatible with the CSS/script changes -- so the site is deployed, but the view is broken because of the mismatched styles.css

Confirmed that the customizations that had been made are no longer relevant for the deleted files and merged in the missing changes from the ones that still were relevant

[jeffhandley]

Thanks for figuring this out!

[Copilot]

Pull request overview

Removes stale “overwrite” chrome assets that were shadowing the newly generated SourceBrowser UI during index builds, and refreshes the remaining override (header.html) to match the new base header while keeping the “.NET Source Browser” branding.

Changes:

• Delete stale override assets (styles.css, overview.html, SolutionExplorer.html) so the generated/base chrome is served.
• Update overwrite/index/header.html to include the base header’s meta tags and mobile paneToggle support while retaining “.NET Source Browser” text.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/index/overwrite/wwwroot/styles.css	Removed stale overridden stylesheet so the current generated/base styling is used.
src/index/overwrite/index/overview.html	Removed stale overridden overview page so the stamped/generated overview is used.
src/index/overwrite/index/SolutionExplorer.html	Removed empty Solution Explorer override so the generated tree page is served.
src/index/overwrite/index/header.html	Rebased override on the new base header (meta tags + mobile pane toggle) while keeping .NET branding.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.