feat: add new commands for completion and migration in pipectl

[vedantlavale]

Summary

Updates the pipectl CLI documentation in docs-dev and docs-v1.0.x to match the current source code.

Changes

• Removes pipectl init from the "Available Commands" help output (command was removed in Remove pipectl init command #5958)
• Adds completion, migrate, and plugin to the "Available Commands" help output
• Removes the "Generating an application config" section documenting the removed pipectl init command
• Adds a new "Migrating application configs and database" section documenting:
  • pipectl migrate application-config
  • pipectl migrate database
• Adds a new "Pushing a plugin" section documenting pipectl plugin push

Why we need it

pipectl init was removed from the codebase but is still documented as an available command. Users following the official documentation currently hit a dead end.

At the same time, pipectl migrate (the replacement workflow) and pipectl plugin push already exist in the source code but are undocumented, making them difficult for users and plugin authors to discover.

Which issue(s) this PR fixes

Closes: #6750

Does this PR introduce a user-facing change?

How are users affected by this change

CLI documentation now accurately reflects the currently available commands. Users can discover and use pipectl migrate and pipectl plugin push through the official docs.

Is this a breaking change?

No

How to migrate (if breaking change)

N/A

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Updates the pipectl CLI user guide docs to reflect current commands, removing references to the deprecated init workflow and documenting newer migrate and plugin functionality.

Changes:

• Updates “Available Commands” to remove init and add completion, migrate, and plugin
• Replaces the removed pipectl init documentation with pipectl migrate documentation (application-config + database)
• Adds documentation for pipectl plugin push

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
docs/content/en/docs-v1.0.x/user-guide/command-line-tool.md	Updates the documented CLI help output to match current commands
docs/content/en/docs-dev/user-guide/command-line-tool.md	Updates command list and replaces init docs with migrate and plugin push documentation

[vedantlavale]

@khanhtc1202 , @rahulshendre , @Ayushmore1214 hey, could someone take a look at this when free?
fixed some outdated pipectl docs and added docs for a couple missing commands

[rahulshendre]

Hey @vedantlavale, sorry for the delay, we missed this earlier.

Please have a look at this comment - here. Let's discuss more of the changes needed in the docs with the maintainers in the next community meeting before proceeding further.

Since @A-d-i-t-y is also working in a similar area, it would be great if you both could coordinate on the related changes.