[Change] Deprecate former plan backlog-edit verbs and re-home project migration

[djm81]

Type

Change / Follow-up

Parent

• Parent Feature (modules repo): specfact project validation context adapters #144
• Cross-repo Parent User Story: [User Story] Harden CLI command guidance, command inventory, and package-manager runtime checks specfact-cli#594
• Cross-repo Parent Feature: [Feature] Marketplace Module Distribution specfact-cli#353
• Related core issue: [Change] Remove flat alias module diagnostics from root CLI errors specfact-cli#605

Why

The former plan command surface still contains backlog-shaped editing verbs from an older product direction where SpecFact CLI was positioned as a universal I/O interface. That positioning no longer applies. Backlog items, refinement, provider sync, Definition-of-Ready checks, and backlog hierarchy are now owned by nold-ai/specfact-backlog.

Keeping local project-plan editing verbs such as add-feature, add-story, update-idea, update-feature, and update-story creates duplicated workflow ownership and invites users to edit project-bundle data directly instead of using the backlog module as the canonical backlog interface.

What Changes

• Treat plan add-feature, plan add-story, plan update-idea, plan update-feature, and plan update-story as deprecated compatibility mappings.
• Warn users that those backlog-shaped plan editing verbs are deprecated and scheduled for removal starting with version 0.50.x.
• Point users from deprecated plan editing verbs to canonical specfact backlog ... workflows or docs.
• Keep only non-backlog project lifecycle behavior from the former plan surface as candidates for specfact project ... re-homing.
• Keep project artifact migration as a candidate for specfact project migrate ....
• Do not restore specfact plan ... or specfact migrate ... as root flat commands.

Acceptance Criteria

• Backlog-shaped former plan verbs emit a deprecation warning if compatibility mappings remain.
• Deprecation warning says removal starts with SpecFact 0.50.x.
• Deprecated plan edit verbs point users to specfact backlog ... workflows or docs.
• Valuable non-backlog plan verbs are re-homed under specfact project ... or explicitly retired.
• Project artifact migration is re-homed under specfact project migrate ... or explicitly retired.
• specfact-project/module-package.yaml no longer advertises unreachable plan root command surface unless intentionally mounted as a nested compatibility path.
• Module docs, command docstrings, generated command references, and tests align with the chosen command surface.

OpenSpec

• Change proposal: project-plan-backlog-edit-deprecation
• Source repository for proposal: nold-ai/specfact-cli
• Implementation repository: nold-ai/specfact-cli-modules

Notes

This is a follow-up and should not be bundled into the current flat-alias diagnostic fix unless explicitly pulled forward.