Stop a self-referential node_modules symlink breaking the payload build

`server/node_modules` was tracked as a SYMLINK to its own absolute path:

    120000 blob ... server/node_modules -> /home/owner/Downloads/remote_display/server/node_modules

It came in with the #283 merge. Any attempt to resolve it is an ELOOP, so the
payload build died at the staging step with

    cp: cannot stat 'server/node_modules': Too many levels of symbolic links

and a fresh checkout gets a server/ whose dependencies cannot resolve at all.

.gitignore only had `node_modules/`, and a trailing slash matches DIRECTORIES —
which is exactly how a symlink of that name slipped past it. Both forms are listed
now, so the same mistake cannot be committed again.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014kfhrUPit5MCqxeTQyqr56

.gitignore

@@ -1,5 +1,10 @@
 # Dependencies
 node_modules/
+# No trailing slash as well: `node_modules/` matches DIRECTORIES only, so a SYMLINK named
+# node_modules is not ignored by it. That is not hypothetical - an absolute, self-referential
+# `server/node_modules -> /home/.../server/node_modules` was committed in the #283 merge and broke
+# the payload build with "cp: Too many levels of symbolic links".
+node_modules
 
 # Databases: SQLite files, WAL/SHM sidecars, and any .db.<suffix> backups
 # (e.g. .db.devbak), anywhere in the tree - never commit a database.

server/node_modules

@@ -1 +0,0 @@
-/home/owner/Downloads/remote_display/server/node_modules