feat(message): Add mrkdwn parameter for Slack formatting

[bob-bot]

Summary

Adds an optional mrkdwn boolean parameter to the message step that enables Slack mrkdwn formatting when sending messages via Slack notifiers.

Closes #1024

Problem

Currently, the message step sends plain text to Slack using plain_text block type, which means formatting like *bold*, _italic_, and <url|text> links don't render. Users who rely on notifiers cannot send formatted messages.

Solution

Added an optional mrkdwn parameter that switches the Slack text block type from plain_text to mrkdwn, enabling Slack's markdown-like formatting.

Changes

File	Description
internal/resources/flowpipe_pipeline_step_message.go	Added Mrkdwn field, updated Equals, GetInputs2, SetAttributes
internal/resources/flowpipe_pipeline_schema.go	Added mrkdwn to message step schema
internal/primitive/message.go	Extract mrkdwn flag, conditionally use MarkdownType
internal/primitive/message_test.go	Added 3 new test functions with 10 sub-tests

Usage

step "message" "alert" {
    notifier = notifier.slack_ops
    text     = "*Bold* and _italic_ with <https://example.com|links>"
    mrkdwn   = true
}

Block JSON Comparison

Without mrkdwn (default):

{"type": "section", "text": {"type": "plain_text", "text": "*bold*"}}

With mrkdwn=true:

{"type": "section", "text": {"type": "mrkdwn", "text": "*bold*"}}

Test Plan

• Unit tests added and passing (12 total message tests)
• Functional test with real Slack webhook confirms formatting difference
• Backward compatible - existing pipelines work unchanged

=== RUN   TestMessageStepSlackMessagePlainText
--- PASS: TestMessageStepSlackMessagePlainText (0.00s)
=== RUN   TestMessageStepSlackMessageMrkdwn
--- PASS: TestMessageStepSlackMessageMrkdwn (0.00s)
=== RUN   TestMessageStepSlackMessageMrkdwnComparison
--- PASS: TestMessageStepSlackMessageMrkdwnComparison (0.00s)

Supported Formatting

Syntax	Result
*bold*	bold
_italic_	italic
~strike~	strikethrough
`code`	inline code
<https://url|text>	clickable link

Notes

• The mrkdwn parameter only affects Slack integrations
• Email and MS Teams integrations ignore this parameter
• Testing revealed Slack mobile partially formats plain_text (bold/italic/code) but not links - using mrkdwn=true ensures consistent cross-platform behavior

🤖 Generated with Claude Code

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[github-actions]

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