Discord changes

[zeebie-the-zebra]

What changed

Full rebuild/refresh of the plugins/discord/ plugin tree, replacing the previous 6-file patch with the complete active plugin source.

Summary

• New code: api, cognition, conversation, voice, vision, transport, memory, models, presence, proactive, runtime, schedule, statuses, storage, hooks, lib, observability, sapphire, routes, tools
• Updated existing: README.md, daemon.py, plugin.json, tools/discord_tools.py, web/index.js
• Removed: tests/test_auto_reply_gate.py (subsumed by the newer test suite under tests/)
• Local hygiene: plugins/discord/.gitignore added with pycache/ so Python caches are never tracked

Scope

This PR is the discord plugin only. I do not own core — anything outside plugins/discord/ in this branch is not part of this contribution. ddxfish owns the core, please review and mergefrom there.

Testing

• Local: pytest run against the new tree passes the suite that previously lived next to the plugin
• Manual: not run end-to-end against a live Discord guild in this PR — happy to do that as a follow-up if you want, or take direction on what you'd like exercised before merge

Notes / things worth a look

• plugin.sig was a deleted file in my working tree during this work; it is not part of the commit. Regenerate before shipping if your release flow signs it.
• Many .py files came through with the executable bit set (mode 755). Python source doesn't need it; happy to flatten to 644 in a follow-up commit if you want clean mode bits in
  the tree.
• The PR shows "no changes to compare" at the moment of creation because fork dev and discord-changes are at the same commit. It will populate as soon as your dev moves forward or I add another commit.

How to review

Two commits in order:

1. 8428912 — refresh of the existing tracked files (README, daemon, plugin.json, tools, web UI, removed old test)
2. e4c7f9d — bring over the full plugin tree (264 files, +34,169 / -14)

Review commit 1 first to see the targeted edits, then commit 2 for the bulk add.