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

README.md

@@ -76,6 +76,15 @@ Installer env overrides: `MCODE_SL_ITEMS` (item list), `MCODE_SL_INTERVAL`, `MCO
 curl -fsSL https://git.itsaygea.com/admin/mcode-sl/raw/branch/main/install.sh | bash -s -- --uninstall
 ```
 
+## Documentation
+
+- `AGENTS.md` — operating instructions for humans + agents (incl. Gitea SSH notes)
+- `CURRENT_STATE.md` — where the project stands and the exact next action
+- `TODO.md` — prioritized work with acceptance criteria
+- `CHANGELOG.md` / `TRIALS.md` — change log and experiment index
+- `docs/` — decisions (ADR-style), feature matrix, handoff protocol
+- `handoffs/` — stage continuation records; `tooling/` — verified toolchain
+
 ## Development
 
 Requires `jq` + `curl`; `secretvault` optional (fallback: credential.json); `python3` for the config merge. Test locally: