Milestone 2: Federated Search

We will implement Federated Search functionality that allows users to discover and access federated repositories, organizations, and users without copy-pasting URLs.

Users will be able to enter "repo@orga@server" in the search bar and the local instance will display repository stubs for federated content.
We will implement UI representations for stubs and enable users to fetch federated repository objects by pasting remote URLs into the search bar, requiring Accept: application/activity+json header support on repository and user paths.
Additionally, we will deliver a proof-of-concept for an updated threat-model, using the Threagile threat modeling tool to ensure security considerations are addressed as federation capabilities expand. This milestone represents significant effort as it fundamentally changes how users discover and interact with federated content across the forge network.

A.C.:

Scenario works as described here: forgejo/sustainability@d8921b4858/2025/2025-10-01-sta-federation/considerations.md (milestone2-federated-search)
threats are modeled & report is generated continuously by ci

Deliveries:

Architercture
threat-workshop for newly introduced repository search: #89
threat-tool configured: https://repo.prod.meissa.de/meissa/forgejo-threats
Code
(wip) doc: add federated search documentation: #74
(wip) Enhance webfinger for the upcoming actor types like repository or organization: forgejo/forgejo#10107
Create a federated user type: forgejo/forgejo#10434 (merged)
(wip) Create a federated repository: forgejo/forgejo#10453
(wip) threat-analysis: add search threagile model: #83
create webfinger and search provider: forgejo/forgejo#10929