chore: fill or remove RSR template placeholders

openssf-compliance.yml fails when any of the thirteen files it checks
still contains a {{PLACEHOLDER}} token. This clears them.

Three kinds of change, no invention:

The "TEMPLATE INSTRUCTIONS (delete this block before publishing)" comment
is deleted. The template says to delete it, and it is where every legend
line lives -- so a large share of the reported tokens were the file
documenting its own placeholders, not real unfilled fields.

Tokens derivable from the repository are filled: owner and repo from the
git remote, project name, year, forge, main branch, contact email.

PGP and website lines are removed rather than filled, because nothing
true could go in them. https://github.com/<user>.gpg returns HTTP 200 for
every account; with no key uploaded the body is a stub reading "This user
hasnt uploaded any GPG keys". No key is published for either account
here, and commit signing in this estate is SSH, which is unrelated. Only
one repository in the estate has a domain, so {{WEBSITE}} likewise has no
correct value. The template sanctions this: "Optional: Remove sections
that dont apply (e.g. PGP if you dont use it)." A security policy telling
a researcher to encrypt to a key that does not exist is worse than one
that does not mention encryption.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Signed-off-by: Jonathan D.A. Jewell <6759885+hyperpolymath@users.noreply.github.com>

Author: hyperpolymath

CONTRIBUTING.md

@@ -57,7 +57,7 @@ safe-brute-force/
 
 **Before reporting**:
 1. Search existing issues
-2. Check if it's already fixed in `{{MAIN_BRANCH}}`
+2. Check if it's already fixed in `main`
 3. Determine which perimeter the bug affects
 
 **When reporting**: