1.0: Remove stack leftovers from code, help and docs · Issue #1331 · permadeath.com/atgc

Goal: stack verbs, help and docs match the one-pull-per-branch model, and stack mark cannot be fed git options.

major: The public site advertises stack create and stack resubmit. www/src/pages/index.astro:139-146.
minor: stack mark passes the name to git branch as an option. src/cmd/stack/marks.rs:225, 229.
minor: AGENTS.md tells agents to run refused stack verbs. AGENTS.md:73-84.
minor: The mid-rebase error names stack sync. src/clients/git/run.rs:425.
minor: Two marks on one commit list one as out of range. src/cmd/stack/marks.rs:130.
minor: stack link checks arity before its refusal. src/cmd/stack/write.rs:216.
minor: stack mark exits 1 for a missing remote. src/cmd/stack/read.rs:221, 236.
minor: stack view <pull> leaves the pull out of its advice. src/cmd/stack/read.rs:43.
minor: CONTRIBUTING.md says Change-Id matches stacked pulls. CONTRIBUTING.md:72.
minor: stack help says Tangled has one pull per branch. src/main.rs:303.