docs: add ACP and internal systems implementation guides

- add ACP user and developer docs covering setup, lifecycle, callbacks,
  permissions, tool rendering, and runtime behavior
- add developer guides for agent loop, provider runtime resolution,
  prompt assembly, context caching/compression, gateway internals,
  session storage, tools runtime, trajectories, and cron internals
- refresh architecture, quickstart, installation, CLI reference, and
  environments docs to link the new implementation pages and ACP support

website/docs/reference/cli-commands.md

@@ -44,6 +44,7 @@ hermes [global-options] <command> [subcommand/options]
 | `hermes pairing` | Approve or revoke messaging pairing codes. |
 | `hermes skills` | Browse, install, publish, audit, and configure skills. |
 | `hermes honcho` | Manage Honcho cross-session memory integration. |
+| `hermes acp` | Run Hermes as an ACP server for editor integration. |
 | `hermes tools` | Configure enabled tools per platform. |
 | `hermes sessions` | Browse, export, prune, rename, and delete sessions. |
 | `hermes insights` | Show token/cost/activity analytics. |
@@ -283,6 +284,29 @@ Subcommands:
 | `identity` | Seed or show the AI peer identity representation. |
 | `migrate` | Migration guide from openclaw-honcho to Hermes Honcho. |
 
+## `hermes acp`
+
+```bash
+hermes acp
+```
+
+Starts Hermes as an ACP (Agent Client Protocol) stdio server for editor integration.
+
+Related entrypoints:
+
+```bash
+hermes-acp
+python -m acp_adapter
+```
+
+Install support first:
+
+```bash
+pip install -e '.[acp]'
+```
+
+See [ACP Editor Integration](../user-guide/features/acp.md) and [ACP Internals](../developer-guide/acp-internals.md).
+
 ## `hermes tools`
 
 ```bash