chore: genericize plugin manifests for public release

main is now the shareable artifact: placeholder host and clientId, no
instance-specific hostnames, marketplace renamed to cybercove-labs.

The filled-in manifest for the live instance lives on branch
instance/dnspegasus and is installed with a #ref fragment, which
`claude plugin marketplace add` honors and persists even though it is
absent from --help (verified on Claude Code 2.1.220).

README: plugin install is now path A, documenting both the fork-and-edit
and the #ref branch approaches; remaining paths renumbered B/C/D.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

plugin/.claude-plugin/plugin.json

@@ -2,9 +2,9 @@
   "$schema": "https://anthropic.com/claude-code/plugin.schema.json",
   "name": "shared-memory",
   "version": "0.1.0",
-  "description": "Shared persistent memory and snippet library for Claude Code sessions, backed by memory.dnspegasus.net and authenticated with Authentik OIDC.",
+  "description": "Shared persistent memory and snippet library for Claude Code sessions, backed by your own shared-memory server and authenticated with OIDC.",
   "author": {
-    "name": "jknapp"
+    "name": "CyberCove Labs"
   },
-  "homepage": "https://memory.dnspegasus.net"
+  "homepage": "https://repo.anhonesthost.net/cybercove-labs/shared-memory"
 }