docs(TASK-097): add the Mesh hub, commands, configuration and trust-model pages
Derived from the code repo at feat/PLAN-mesh:
- Mesh.md: assets/config-template.yaml, src/config/mesh_config.rs,
src/mesh/identity.rs, src/config/session.rs, src/repl/mesh.rs,
src/mesh/announce.rs, src/function/mesh.rs, src/mesh/message.rs,
src/mesh/node.rs, src/supervisor/notification.rs, src/mesh/notify.rs,
assets/envoy/config.yaml, assets/envoy/tools.py, src/config/mesh_envoy.rs,
src/function/mod.rs, src/mesh/brief.rs, src/config/mesh_digest.rs,
src/mesh/card.rs, src/mesh/mod.rs, src/mesh/lock.rs, src/mesh/pending.rs,
src/mesh/knocks.rs, src/mesh/schema.rs, src/mesh/fuzz/mod.rs,
.github/workflows/ci.yaml, scripts/mesh-interop/README.md,
scripts/mesh-netns/README.md, src/mesh/conformance/netns.rs
- Mesh-Commands.md: src/repl/mesh.rs (VERBS, help, previews and results),
src/mesh/trust.rs (MESH_OFF), src/mesh/node.rs (MESH_ALREADY_ON),
src/mesh/lock.rs, src/mesh/card.rs (StatusError), src/mesh/r3/error.rs,
src/config/macros.rs, src/repl/mod.rs, src/config/request_context.rs
- Mesh-Configuration.md: assets/config-template.yaml,
src/config/mesh_config.rs (defaults, validate, TryFrom<RawMeshInterface>,
render_mesh_info), src/mesh/announce.rs, src/mesh/limits.rs,
src/config/paths.rs, src/config/request_context.rs
- Mesh-Trust-Model.md: src/mesh/trust.rs (authorize, identity_standing,
note_key_change, key_change_text, mutations), src/mesh/knock.rs,
src/mesh/knocks.rs, src/mesh/identity.rs, src/mesh/lock.rs,
src/repl/mesh.rs