…on (#2885)

…tering, and other gaps

- Add new Coding Harnesses page (docs/features/harnesses/index.md) covering
  claude-code, codex, opencode, pi harness types, field reference, recipes
  for sequential and parallel harness dispatch, limitations, and hook behavior
- Add Coding Harnesses to nav.yml (Features section, after MCP Mode)
- Update multi-agent/index.md: add Harness-Backed Sub-Agents section
- Update background-agents/index.md: add Using Harness Sub-Agents section
- Update configuration/agents/index.md:
  - Add harness field to Properties Reference table and Full Schema YAML
  - Add Agent-Switching Commands subsection with handoff/transfer_task comparison
  - Expand welcome_message description (Markdown rendered, not sent to model)
- Update configuration/hooks/index.md:
  - Add cross-link to Coding Harnesses page in model_id note
  - Add link to examples/snapshot_hooks.yaml
- Update configuration/models/index.md: add link to examples/task_budget.yaml
- Update configuration/tools/index.md:
  - Expand Tool Instructions section with ORIGINAL_INSTRUCTIONS placeholder docs
  - Expand Deferred Tool Loading section with full explanation and example link
  - Add link to examples/lifecycle.yaml in Lifecycle section
- Update tools/fetch/index.md: add Domain Filtering summary section with
  example links (fetch_domain_filtering.yaml, remote_mcp_allow_private_ips.yaml)
- Update tools/filesystem/index.md: expand Post-Edit Hooks section with
  field table, error behavior, and link to examples/post_edit.yaml
- Update tools/mcp/index.md: expand TOON section with regex semantics and
  link to examples/github-toon.yaml
- Update features/skills/index.md: add links to skills_inline.yaml and
  skills_filter.yaml examples
- Update concepts/multi-agent/index.md: add link to sub-agents-from-catalog.yaml

B1: before_llm_call/after_llm_call DO fire for harness agents - remove
    incorrect 'will not fire' claim. model_id is set to the harness label
    (e.g. claude-code) rather than a canonical provider/model string.

B2: Token usage IS tracked when the CLI reports it. Claude Code and Codex
    both report usage data. Replace 'unavailable' bullet with accurate
    description of conditional tracking.

B3: Remove incorrect pi.ai/talk link (Inflection AI consumer chatbot).
    Replace with 'Refer to the pi CLI documentation for installation.'

N1: Replace all prose 'docker-agent' with 'Docker Agent' per STYLE.md in
    harnesses/index.md, multi-agent/index.md, and background-agents/index.md.
    (Repo/URL path 'docker/docker-agent' is unchanged.)

N2: Fix agent names in recipe YAML to use hyphens (claude-coder, codex-coder)
    matching examples/coding_harnesses.yaml and
    examples/coding_harness_background_agents.yaml. Updated in
    harnesses/index.md, multi-agent/index.md, and background-agents/index.md.

N3: Fix blocked_domains bullet in fetch/index.md Domain Filtering section -
    was self-contradictory ('takes priority over allowed; cannot be combined').
    Corrected to: 'mutually exclusive with allowed_domains (a config error is
    thrown if both are set)'.

N4: Broaden allow_private_ips scope note in fetch/index.md - flag is also
    supported on api, openapi, a2a, and remote mcp toolsets, not just fetch.

N5: Add 'toolsets: are silently ignored when harness: is set' note to the
    harness row in the agents/index.md Properties Reference table.

Automated changelog update for release v1.70.2

Assisted-By: Docker Agent

docs: update CHANGELOG.md for v1.70.2

docs: document coding harnesses and fill P0/P1/P2 documentation gaps

fix: keep failed chat continuations out of conversation cache

fix: github-copilot Responses API auto-selection and error preservation

fix: update github-copilot model from gpt-4o to gpt-4.1

Assisted-By: docker-agent

chore(config): freeze v9 and bump latest to v10