Remove stackpop references ahead of the EdgeZero move to IABTechLab #1322

Description

EdgeZero is moving from github.com/stackpop/edgezero to github.com/IABTechLab/edgezero. The transfer has not happened yet. GitHub will redirect the old URL after the move, but our builds should not depend on that redirect. It stops working if anyone recreates stackpop/edgezero. Trusted Server should end up with no stackpop references at all.

git grep -i stackpop on main finds these:

• EdgeZero git dependencies. Six crates in Cargo.toml and eight packages in Cargo.lock, all pinned to rev 683202c6. Point EdgeZero dependencies and links at the IABTechLab organization #1323 switches them to the new URL.
• EdgeZero links in docs/superpowers plans and specs. About 60 links to the repo, its issues and its PRs. Point EdgeZero dependencies and links at the IABTechLab organization #1323 updates them.
• stackpop/esi mentions. These are in crates/trusted-server-adapter-fastly/src/esi_assembly.rs, docs/guide/configuration.md and three ESI docs under docs/superpowers. We now take esi = "0.7.2" from crates.io, so the user guide's line about a pinned stackpop/esi parser is stale too.
• fastly.toml author. authors = ["jason@stackpop.com"] needs a new value, which is an owner call.

Six open PRs add new stackpop/edgezero lines and will bring the old URL back unless they rebase onto the new one: #1123, #1175, #1261, #839, #1262 and #1084. The October release branch rc/202610 (#1228) has the same references as main, plus one more plan doc.

The EdgeZero repo has its own sweep to do. Its README, docs and deploy-action guides point at stackpop/edgezero. More important, edgezero-cli templates and the adapter cli.rs files scaffold new projects with github.com/stackpop/edgezero dependencies.

Done when

• EdgeZero transfer to IABTechLab is complete
• Point EdgeZero dependencies and links at the IABTechLab organization #1323 is merged. It has to wait for the transfer, since Cargo cannot fetch the new URL before then.
• stackpop/esi mentions name the esi crate instead, or an IABTechLab home if that repo moves too
• fastly.toml authors is updated
• The open PRs listed above are rebased and add no stackpop lines
• rc/202610 is updated
• git grep -i stackpop on main returns nothing
• A CI check fails on new stackpop references so the count stays at zero

Affected area

CI / Tooling, Documentation