docs: AGENTS.md + evidence-backed scaffold (state, trials, decisions, handoff)

- AGENTS.md operating rules incl. Gitea SSH port-2222 note + known_hosts incident
- CURRENT_STATE / TODO / CHANGELOG / TRIALS
- trials: endpoint-key pairing; config-merge safety matrix 14/14 (verify.sh + output)
- docs: DECISIONS (mcode 0.6.12 bundle facts, digest-pinned), FEATURE-MATRIX, PROJECT-HANDOFF
- handoffs: TEMPLATE + 2026-10-19 initial-install record

tooling/README.md

@@ -0,0 +1,18 @@
+# tooling
+
+Verified tools for this project (host `mewtwo`, 2026-10-19):
+
+| Tool | Version/notes | Required for |
+|---|---|---|
+| bash | system | everything |
+| jq | system | `zai-usage.sh` parsing |
+| curl | system | quota fetch |
+| python3 | stdlib; PyYAML present locally (optional, adds YAML validation) | `install.sh` merge |
+| git | SSH remote | pushes |
+| secretvault | `~/.local/bin/secretvault` CLI; MCP `create_secret` to provision | key resolution (fallback: credential.json) |
+
+Setup on a new machine: `sudo`-install `jq curl python3` if missing, create the
+`zai_api_key` SecretVault secret, then the one-liner from `README.md`.
+
+macOS caveats (designed for, untested): no `flock`/`setsid` → script degrades to plain
+background refresh; `date -r` fallback path; BSD `install` supports `-m 755`.