fix(init): create start.prompt.md and fix next steps panel (#603)

[sergio-sisternes-epam]

Summary

Fixes #603 — apm init showed a Next Steps panel that directed users through an incorrect workflow. Following the instructions led to a dead end because start.prompt.md was never created and apm compile was referenced incorrectly.

Changes

1. Create start.prompt.md during init

• Regular (non-plugin) projects now get a minimal start.prompt.md with frontmatter
• Brownfield safety: existing start.prompt.md files are never overwritten
• Plugin mode (--plugin) does NOT create start.prompt.md
• Written with encoding="utf-8" for Windows compatibility

2. Fix Next Steps panel

• Removed: Compile agent context: apm compile (unrelated to apm run)
• Added: Edit your prompt: start.prompt.md
• The workflow now works end-to-end: init -> setup runtime -> edit prompt -> run

3. Updated Created Files table

• start.prompt.md now appears in the Created Files table when generated

Files Changed

• src/apm_cli/commands/init.py — Create start.prompt.md, fix next steps, update files table
• tests/unit/test_init_command.py — 5 new tests + 4 updated tests
• tests/unit/test_init_plugin.py — 1 new test (plugin mode doesn't create start.prompt.md)
• CHANGELOG.md — Add fix entry

Testing

All 3795 tests pass (39/39 init-specific tests pass).

[Copilot]

Pull request overview

Fixes the apm init -> apm run start onboarding flow by ensuring a runnable starter prompt exists and updating the printed Next Steps to match the intended workflow.

Changes:

• Create start.prompt.md during apm init for non-plugin projects (without overwriting existing files).
• Update the Next Steps panel to remove the unrelated apm compile step and direct users to edit start.prompt.md.
• Update and add unit tests, and add a changelog entry for the fix.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
src/apm_cli/commands/init.py	Creates start.prompt.md, updates Created Files output, and fixes Next Steps messaging.
tests/unit/test_init_command.py	Updates existing init tests and adds new coverage for the starter prompt and next-steps output.
tests/unit/test_init_plugin.py	Adds coverage ensuring plugin mode does not create start.prompt.md.
CHANGELOG.md	Adds an Unreleased “Fixed” entry describing the init onboarding fix.