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

[mdheller]

Summary

This PR captures the remaining repo-local prep needed before opening an upstream ecosystem/landscape submission.

It adds:

• assets/tritrpc.svg
• LANDSCAPE.md

Why

TriTRPC already has the protocol surface needed for external positioning as an Agent Protocols project:

• stable TritRPC v1 specification
• canonical encoding contract
• cross-language parity across Rust and Go
• strict fixture verification
• authenticated envelope framing

The missing blocker on the repo side was simply having a reusable logo asset and one in-repo note that captures the intended category, tag, one-line description, and listing metadata.

Scope

This PR does not change the protocol, fixtures, or implementation.
It only adds lightweight brand/submission-prep artifacts so the external listing work is captured in the repo itself.

Intended external positioning

• Category: Agent Protocols
• Summary tag: Open Source
• One-line description: Deterministic, authenticated RPC protocol with canonical fixtures and cross-language parity for agent interoperability.

[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 -> Agent Protocols
• insert after Model Context Protocol

Upstream-ready snippet:

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

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

• assets/tritrpc.svg
• LANDSCAPE.md

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

1. copy assets/tritrpc.svg into agentic-landscape/logos/tritrpc.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

[mdheller]

Current repo-side status check:

• PR is still draft
• GitHub currently reports it as mergeable
• combined status for head commit adc01bddd8ec72829b1570cb5c3d30afa850e78d is empty (no status contexts reported through the connector)

So from the repo side this now looks like a human-review / merge decision, not a CI blocker.

Remaining external blocker is still upstream landscape submission access to agentic-community/agentic-landscape, where the connector currently has pull: true and push: false.

[mdheller]

@copilot fix the failed checks