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/developer-guide/trajectory-format.md

@@ -0,0 +1,56 @@
+---
+sidebar_position: 10
+title: "Trajectories & Training Format"
+description: "How Hermes saves trajectories, normalizes tool calls, and produces training-friendly outputs"
+---
+
+# Trajectories & Training Format
+
+Hermes can save conversation trajectories for training, evaluation, and batch data generation workflows.
+
+Primary files:
+
+- `agent/trajectory.py`
+- `run_agent.py`
+- `batch_runner.py`
+- `trajectory_compressor.py`
+
+## What trajectories are for
+
+Trajectory outputs are used for:
+
+- SFT data generation
+- debugging agent behavior
+- benchmark/evaluation artifact capture
+- post-processing and compression pipelines
+
+## Normalization strategy
+
+Hermes converts live conversation structure into a training-friendly format.
+
+Important behaviors include:
+
+- representing reasoning in explicit markup
+- converting tool calls into structured XML-like regions for dataset compatibility
+- grouping tool outputs appropriately
+- separating successful and failed trajectories
+
+## Persistence boundaries
+
+Trajectory files do **not** blindly mirror all runtime prompt state.
+
+Some prompt-time-only layers are intentionally excluded from persisted trajectory content so datasets are cleaner and less environment-specific.
+
+## Batch runner
+
+`batch_runner.py` emits richer metadata than single-session trajectory saving, including:
+
+- model/provider metadata
+- toolset info
+- partial/failure markers
+- tool statistics
+
+## Related docs
+
+- [Environments, Benchmarks & Data Generation](./environments.md)
+- [Agent Loop Internals](./agent-loop.md)