#2842 gatorwalk-factory: scrub the swamp-club Lab from everything a public user sees, so it never reads as an option

The swamp-club Lab tracker is for the swamp-club team's own repositories only. It must never be presented, or read, as an option for anyone else. The first acceptance run of the authoring skill (#2818) offered it in the interview. #2818 removed it from references/authoring.md and added a test (skill_test.ts, 'authoring never offers the swamp-club Lab'). Everything else that ships with the extension still presents it.

Where it shows today (gatorwalk-factory/, counts of swamp-club or Lab mentions)

Skill, which is read by every agent the skill is installed for:

• SKILL.md: the examples bullet lists swamp-club-swamp-extensions.yaml, and the claim paragraph names Lab ticket ids.
• references/driving.md (10): Start from a ticket, Keep the ticket in step, retarget (Lab externalRefs), and the claim refusal 'driven by issue-lifecycle here'.
• references/scenarios.md (1): the example externalRefs are swamp-club.
• references/examples/swamp-club-swamp-extensions.yaml, its .md mapping, and 14 saved scenarios under examples/scenarios/swamp-club-swamp-extensions/.
• references/examples/starter.yaml (2): its description says stages project Lab statuses so a work item can drive a swamp-club issue, and its projection keys (triaged) are Lab statuses. That key is also not one of the built-in tracker's default statuses.
• references/examples/build-swamp-extension.yaml and .md, plus the plan-to-release scenario.

Engine and docs:

• init --from: swamp-club-swamp-extensions is one of the bundled starters (_lib/engine/starters.ts, generated by scripts/gen_starters.ts), so the factory's method schema advertises it.
• README.md (38): the swamp-club Lab setup section and Lab examples throughout.
• DESIGN.md (58): 'The swamp-club Lab adapter' and Lab-based examples.
• extensions/models/tracker/swamp_club.ts: the @swamp/gatorwalk-factory/swamp-club model type ships in the extension, so model type search lists it.
• extensions/models/tracker/builtin.ts (1): a comment.

Change

• Public text (skill, README, examples, starters) names only the built-in tracker (the default) and Linear. Examples use neutral ids and externalRefs (built-in or Linear), and status keys the built-in tracker has.
• The swamp-club-swamp-extensions factory definition and its scenarios move out of the shipped skill and out of init's starters, to where the swamp-club team keeps its own factory (for example this repo's factories/ and scenarios/). The tests that pin it (examples_test, the starters list) move with it.
• Extend the #2818 guard test to the whole skill directory: no swamp-club or Lab mention anywhere in the shipped skill, and no starter named for it.

Decide first (Seth)

• The @swamp/gatorwalk-factory/swamp-club adapter ships in the public extension, so model type search shows it. Should it move to a separate team-only extension, or stay and just go unmentioned?
• DESIGN.md is an engineering document. Should its Lab sections go with the adapter, or be rewritten around the built-in tracker?
• Some sessions in flight edit these files (#2781 examples and review prompts, #2778 skill). Order this after them, or rebase them.

Done when

• A fresh agent with the installed skill, asked to set up a gatorwalk factory or start one from a ticket, never mentions swamp-club or the Lab.
• A grep for swamp-club or Lab over the shipped skill, README and starters finds nothing, enforced by a test.
• swamp-club's own gatorwalk use (this repo's issue process) still validates, from its new location.