feat(slack): Block Kit support for clarify prompts and rich messages

[jarvisxyz]

feat(slack): add Block Kit support for clarify prompts and rich messages

Add robust Slack Block Kit rendering to the Hermes Slack adapter,
replacing plain-text-only clarify prompts with interactive button
interfaces and enabling rich section-based message layout.

Changes:

1. Block Kit Clarify Prompts (send_clarify override)

   • Override base-class send_clarify() with Block Kit buttons
   • Multi-choice (5 or fewer options): one button per choice + Other
   • Multi-choice (more than 5 options): numbered text list + Other
   • Open-ended (no choices): plain text fallback (same as base)
   • Buttons encode clarify_id:choice_index in the value field
   • Other button triggers text-capture via mark_awaiting_text()

2. Clarify Action Handlers

   • _handle_clarify_choice_action: resolves clarify with chosen text,
     updates message to show selection (removes buttons)
   • _handle_clarify_other_action: switches to text-capture mode,
     updates message to show waiting indicator
   • Both handlers include authorization checks (SLACK_ALLOWED_USERS)
   • Registered in connect() alongside existing approval/confirm handlers

3. Rich Message Rendering (_markdown_to_blocks)

   • New module-level utility converts markdown to Block Kit sections
   • Splits on headers (## Title) into separate section blocks
   • Interleaves dividers between sections for visual hierarchy
   • H1/H2 bold, H3+ italic styling
   • Enforces Slack limits (50 blocks, 3000 chars/section)
   • Conservative: does NOT convert lists/tables/code (mrkdwn handles these)

4. Enhanced send() with Block Kit

   • When rich_messages config is enabled (default: true), messages
     with 2+ header sections are sent as Block Kit blocks
   • Simple messages stay as plain mrkdwn text (preserves URL unfurling)
   • Configurable via platforms.slack.extra.rich_messages: false

5. Enhanced edit_message() with Block Kit

   • Same rich rendering applied to message edits
   • Progress updates with headers render as sections

6. Progress Block Builder (_build_progress_blocks)

   • Static method to render tool-call progress as Block Kit
   • Section block with progress text + context block with indicator

Config Options:

• platforms.slack.extra.rich_messages (default: true)

Tests:

• 23 new tests in test_slack_clarify_buttons.py
• All 287 existing Slack/clarify tests continue to pass

[github-actions]

🔎 Lint report: 2025-07-11.eizus.slack-block-kit vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 9712 on HEAD, 9709 on base (🆕 +3)

🆕 New issues (2):

Rule	Count
invalid-argument-type	1
unresolved-import	1

First entries

gateway/platforms/slack.py:3081: [invalid-argument-type] invalid-argument-type: Argument to bound method `list.append` is incorrect: Expected `dict[str, str | dict[str, str]]`, found `dict[str, str | dict[str, str] | list[dict[str, str | dict[str, str]]]]`
tests/gateway/test_slack_clarify_buttons.py:13: [unresolved-import] unresolved-import: Cannot resolve imported module `pytest`

✅ Fixed issues: none

Unchanged: 5031 pre-existing issues carried over.

Diagnostics are surfaced as warnings — this check never fails the build.