feat(TASK-033): add hook config schema across all scopes

Introduce src/hooks.rs as a types-only module (HookDef, HooksMap) and
plumb hooks:/global_hooks: config fields through every scope:

- Config + AppConfig hooks field, both Default impls, the manual
  from_config copy, and a COYOTE_HOOKS env override
- Role frontmatter: hand-parsed hooks arm, private field, getter, and
  JSON-inline re-serialization in Role::export (malformed maps degrade
  to None)
- AgentConfig + Graph: hooks + global_hooks on both structs, copied in
  AgentConfig::from_graph, with a per-agent global_hooks env override
- paths::hooks_dir() = <config_dir>/hooks with COYOTE_HOOKS_DIR override
- Commented hooks: block in the global config template (global scope
  only; no global_hooks key)

No engine or dispatch logic yet; existing configs parse unchanged.

assets/config-template.yaml

@@ -149,6 +149,18 @@ mcp_tools: null                  # Per-server MCP tool allowlists (glob patterns
                                  #       - list_*
                                  #     slack: []
 
+# ---- Hooks ----
+# Fire-and-forget external commands that run when lifecycle events fire. Each event name
+# maps to a list of named hooks; every listed hook's command runs when that event fires.
+# Hooks never block coyote and never change its output or exit code.
+# See the [Hooks documentation](https://github.com/Dark-Alex-17/coyote/wiki/Hooks) for more details
+hooks: {}                        # Event -> list of named hook commands (default: none)
+                                 # Example:
+                                 #   hooks:
+                                 #     turn.completed:
+                                 #       - name: notify
+                                 #         command: ./hooks/notify.sh
+
 # ---- Auto-Continue (Todo System) ----
 # The auto-continue system provides built-in task tracking for improved reliability.
 # When enabled, the model can create todo lists and the system will automatically