Add .gitattributes and tighten .gitignore

Normalises text to LF and marks the migrated WordPress uploads (204 PNGs,
94 JPGs, plus GIFs/PDFs/ICO/MP4) as binary so git stops trying to diff,
merge or rewrite endings in them. src/styles/global.css came out of the
theme with CRLF endings and is renormalised here in one deliberate pass
rather than leaving it to surprise someone on a later commit -- the
content is byte-identical ignoring whitespace.

.gitignore additionally covers .vscode/, *.log, *.swp, Thumbs.db and all
.env variants -- the last of those matters because scripts/export-wp.mjs
reads the WordPress DB credentials from the environment.

Also corrects the note on the excluded 80MB video: it lives in public/
and Astro copies it into dist/ on every build, so no manual copy step is
needed, contrary to what the old comment claimed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,16 @@
+# Normalise text to LF in the repository and on checkout. global.css was ported
+# from the WordPress theme with CRLF endings and has been renormalised.
+* text=auto eol=lf
+
+# Migrated WordPress uploads and other binaries: never diff, merge or touch endings.
+*.png  binary
+*.jpg  binary
+*.jpeg binary
+*.gif  binary
+*.ico  binary
+*.webp binary
+*.pdf  binary
+*.mp4  binary
+
+# Generated by npm, and pure noise in review.
+package-lock.json -diff linguist-generated=true