brand(agentplane): add logo asset and capture landscape positioning

[mdheller]

Summary

This PR captures the repo-local assets needed to support an eventual external ecosystem / landscape submission.

It adds:

• assets/agentplane.svg
• LANDSCAPE.md

Why

agentplane is now publicly strongest as workflow orchestration / execution control:

• bundle -> validate -> place -> run -> evidence -> replay
• runner-based execution surface
• replay inputs and lifecycle artifacts
• newer runtime governance and receipt-oriented evidence work already on main

The missing repo-local submission plumbing is simply:

• a reusable logo asset
• one in-repo note capturing the intended category, summary tag, and one-line description

Scope

This PR does not change runtime behavior.
It only captures brand / listing-prep assets in-repo.

Intended external positioning

• Category: Workflow Orchestration
• Summary tag: Open Source
• One-line description: Execution control plane for governed bundles, executor placement, and run/replay evidence artifacts.

Note

This branch was cut before the most recent main updates. If GitHub reports conflicts or merge friction, the change should be rebased onto current main because the actual content delta is only these two additive files.

[mdheller]

Refreshed against the current live upstream agentic-community/agentic-landscape data.yml.

Current status from connector permissions:

• upstream repo is reachable
• permissions are pull: true, push: false
• so the actual upstream PR still needs an external submitter path even though the snippet is now stable

Exact current insertion target:

• category: Agentic -> Workflow Orchestration
• insert before Dify to preserve alphabetical order

Upstream-ready snippet:

          - name: Agentplane
            homepage_url: https://github.com/SocioProphet/agentplane
            repo_url: https://github.com/SocioProphet/agentplane
            extra:
              summary_tags: Open Source
            logo: agentplane.svg

This PR now carries the repo-local prerequisites for that upstream step:

• assets/agentplane.svg
• LANDSCAPE.md

And PR #14 carries the separate repo-surface/docs/contracts cleanup that strengthens the public repo itself.

So once upstream write access is available, the remaining work is just:

1. copy assets/agentplane.svg into agentic-landscape/logos/agentplane.svg
2. insert the snippet above in agentic-landscape/data.yml
3. use the prepared one-line description from LANDSCAPE.md / sandbox PR draft in the upstream PR body

One caveat: this branding PR branch was cut before the latest main movement, so if merge friction remains, rebase the two additive files onto current main before merging.