Implements structured interactive prompts with button choices and modal
forms, rendered as Discord embeds + components with auth gating.

New files:
- tools/interactive_prompt_tool.py — schema, validation, tool entry point
- tools/human_input_gateway.py — cross-platform prompt registry (per-session
  wait/resolve, timeout, cleanup)
- tools/discord_auth_helpers.py — shared auth check for interactive views
- tools/discord_interactive_views.py — Discord modal + choice button views
- gateway/platforms/discord_components.py — Discord Components API adapter
- tests/tools/ — 79 tests (4 files)

Modified files:
- gateway/run.py — interactive_prompt_callback wiring + gateway shutdown
  cleanup (clear_all for clarify + interactive prompts)
- gateway/platforms/base.py — send_interactive_prompt adapter method
- plugins/platforms/discord/adapter.py — Discord render override
- agent/agent_runtime_helpers.py, agent/tool_executor.py — tool call paths
- tools/clarify_gateway.py — clear_all() for shutdown cleanup
- toolsets.py — toolset registration

79 tests passing. Docs committed separately.

…ehavior

P1: Fix double-JSON-encoding — detect and pass through already-serialized
JSON strings from production gateway callbacks instead of re-encoding.

P1: Add text-fallback resolution for non-rich platforms — add
get_pending_for_session/mark_awaiting_text/resolve_text_response to
human_input_gateway, wire base-platform send_human_input to mark
text-capture, add gateway intercept for interactive_prompt text replies.

P2: Use config-aware timeout in AIAgent intercepted paths — both
agent_runtime_helpers.py and tool_executor.py now call
get_interactive_prompt_timeout() when timeout_seconds is absent.

P2: Wrap interactive_prompt in _finish_agent_tool in runtime_helpers so
post-tool-call hooks fire (timing, metrics, tracing).

P2: Use get_hermes_home() instead of hardcoded ~/.hermes for upload cache
path in discord_interactive_views.py.

P2: Implement per-policy auth checks — any_allowed_user only checks user
allowlist, any_allowed_role only checks role allowlist,
any_allowed_user_or_role checks union.

P3: Enforce runtime validation — reject invalid display_type and
auth_policy values, clamp timeout_seconds to 60-3600 range.

45 new tests covering all 7 findings.