Remove legacy fastify-based code

[melvincarvalho]

Background

fonstr v0.0.15+ migrated from a custom fastify-based Nostr relay to a thin wrapper around jspod (JavaScriptSolidServer).

Legacy files to remove

File	Description
index.js.legacy	Old fastify-based relay (13KB)
bin/	Old CLI entry point
lib/	Old DID endpoint code
test/	Tests for old architecture
admin.html	Old admin interface
deploy.sh	Old deploy script

Why remove

• Dead code that's never executed
• Confusing for contributors
• Inflates package size
• Tests reference non-existent functions

Notes

• MIGRATION.md documents the transition (keep for reference)
• index.js.legacy was kept initially for reference but can now be removed