Trim the harness to what it needs to keep going

Host:
- test first: a new version is tested where it lies; only an installed
  version goes to versions/, and instances run from there
- data/ and public/ are shared by all versions; no snapshots; rollback
  restores code only
- no re-delivery, status.json, list, remove/archive, smoke test, data/
  hiding, or stdin timeout; rollback needs a version
- supervisor.rs split out; one place for installing a version
- init only writes the agent folder; run installs it like any actor
- console: @actor, text to the agent, /help, /quit

Agent:
- every text goes out as a broadcast; 5-line prompt; 5 tools that describe
  themselves; turn.json only marks an active turn

Docs: PROTOCOL.md, README.md, DECISIONS.md, AGENTS.md rewritten.
Examples: only notes and notes-v2.

cli/tests/actors/toolbox/src/main.rs

@@ -146,8 +146,6 @@ fn main() {
                 }
                 Err(error) => io_error(error),
             },
-            Some("crash") if version == "1" => panic!("asked to crash"),
-            Some("crash") => json!({"type": "replayed", "version": version}),
             _ => json!({"type": "error", "error": "unknown message"}),
         };
         reply(&mut out, &message, response);