feat(agents): scaffold workspace on agent add and register

[sytone]

Closes #331

Changes

New: IAgentWorkspaceScaffolder + AgentWorkspaceScaffolder

• Interface defined in BotNexus.Gateway.Contracts
• Implementation wraps BotNexusHome.GetAgentDirectory which provisions workspace from embedded assembly templates on first access
• Registered as singleton in DI

AgentsController.Register

• Accepts optional IAgentWorkspaceScaffolder (backward compatible)
• Calls ScaffoldAsync after config is saved — best-effort, non-fatal (logs warning on failure)

AgentCommands (CLI)

• ExecuteAddAsync and ExecuteWizardAsync now call BotNexusHome.GetAgentDirectory directly (same scaffold trigger) after config save
• Non-fatal: scaffold failure logs a warning but does not fail the agent add command

Tests (13 new)

• AgentWorkspaceScaffolderTests: workspace dir created, scaffold files present, idempotent, returns correct path, sad paths
• AgentCommandsScaffoldTests: agent add creates workspace dir, creates scaffold files, resilient to scaffold failure

All 1649 gateway + 86 CLI + 206 CodingAgent tests pass.

[sytone]

Farnsworth Review -- PR #487

CI: All checks passing
Merge conflicts: CLEAN/MERGEABLE
Conventional commit title: feat(agents): scaffold workspace on agent add and register -- correct

Test coverage: 13 tests covering workspace creation, scaffold files, idempotency, sad paths, CLI resilience to scaffold failure. All 1649 gateway + 86 CLI pass.

Design notes:
IAgentWorkspaceScaffolder delegates to BotNexusHome.GetAgentDirectory which already handles embedded template scaffold on first access -- clean composition, avoids duplication.
Non-fatal best-effort pattern in both controller and CLI is the right call for optional scaffolding.
Optional DI param on AgentsController.Register maintains backward compatibility.

LGTM. Ready to merge.

[sytone]

CI: All checks passing
Merge conflicts: Clean / MERGEABLE
Commit title: Conventional commit format correct
Coverage: 13 tests for IAgentWorkspaceScaffolder, AgentWorkspaceScaffolder, controller/CLI integration
Spec completeness: Closes #331 - IAgentWorkspaceScaffolder + AgentWorkspaceScaffolder wrapping BotNexusHome.GetAgentDirectory; called from AgentsController.Register and CLI wizard/add (best-effort)

LGTM - ready to merge.

[sytone]

Farnsworth Review — PR #487

CI: ✅ All checks passing
Merge conflicts: ✅ Clean (MERGEABLE)
Conventional commit title: ✅ feat(agents): scaffold workspace on agent add and register

Test coverage:

• ✅ 13 tests (scaffolder called on register, best-effort non-fatal, CLI add wizard)
• 1649/1649 pass

Spec completeness vs #331: Delegates to BotNexusHome.GetAgentDirectory existing mechanism — correct approach, avoids duplicating templates. Both AgentsController.Register and CLI wizard paths covered.

LGTM. Ready to merge.

[sytone]

Closing as part of a planned hard-reset of the in-flight branch set so the new domain-model refactor can land on a clean trunk.

Audit verdict: keep

Rationale: Workspace lifecycle; orthogonal.

The new plan (in session state) reshapes core types: Citizen (User+Agent union), Vogen-generated value objects, ThreadId removed in favour of composite ChannelAddress, mark-not-delete compaction, centralised SessionContextProjector, single-path routing. Many in-flight branches touch contracts that are about to change — rebasing later would be more work than rebuilding on the new shape.

If this work is still wanted, refile as a new issue/PR against the post-refactor contracts.