M8F-264: Add M8Flow usage documentation and README updates

[sonal-aot]

JIRA Ticket

M8F-264

Description

Adds a how-to-use.md guide covering the core admin workflows in m8flow, with step-by-step instructions and supporting screenshots.

Sections covered:

• Creating a process group and process model
• Running the default workflow
• Configuring a user task with a web form (JSON Schema)
• Assigning tasks to users via swimlane groups
• Next steps linking to sample templates and connectors documentation

Type

• Feature
• Bug fix
• Documentation
• Other

Changes

• Backend
• Frontend
• Documentation

Testing

Related Issues

Closes #

[github-actions]

PR Agent Review

Blocking issues

1. README formatting regression due to unintended heading promotion
   • Two plain sentences were changed into level-3 headings:
     • ### Once started, open ...
     • ### Once your tenant is created ...
   • This is likely unintentional and can break document structure/TOC hierarchy and readability.
   • Action: Revert both lines to normal paragraph text (remove ###).

Non-blocking suggestions

1. Anchor text mismatch risk
   • In README: Continue with [How to use m8flow](#how-to-use-m8flow)...
   • The section exists, so this should work, but consider consistent title casing between link text and heading (How to Use m8flow) for clarity.
2. Potential doc drift with UI labels
   • New guide relies heavily on exact UI labels/buttons and screenshot-driven steps. These can become stale quickly.
   • Action: Add a short note that labels may vary by version and keep screenshots versioned or periodically validated.

Recommended tests

1. Docs link validation (blocking for docs PRs)
   • Run a markdown link checker across README.md and docs/how-to-use.md to ensure:
     • Internal anchors resolve (e.g., #how-to-use-m8flow, #tenant-creation)
     • Relative links resolve (e.g., docs/how-to-use.md, ../m8flow-backend/...)
2. Markdown lint/structure check
   • Add/execute markdown lint rules to catch accidental heading level changes (like unintended ###) and maintain heading hierarchy.
3. Image reference validation
   • Verify all referenced images in docs/how-to-use.md exist and are correctly named/cased in docs/images/ (important on case-sensitive filesystems).

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