Point one-tap records at the Guide and return Unlike to the parent

[raghubetina]

Why

firstdraft/firstdraft#1005 makes the Compiler emit a one-tap button for a no-input associated create, and a Like/Unlike toggle when the record also has a uniqueness rule over the parent and the signed-in Account References and an owner-authorized destroy. A create returns to the parent page. The destroy keeps its own destination, so Unlike returns to the parent only when the Plan authors destroy.return_to through the parent Reference (for example like.post); otherwise it goes to the ordinary delete destination, which is Home for a Like with no index. The Skill's Like example authored no such return, and its "deployed Compiler may still show a separate Create page" caveat stops being true once #1005 deploys.

This change:

• makes the Like fragment in references/examples.md a byte-for-byte copy of the public Guide's No-input records example (single like.manage_own manage Policy, destroy.return_to through like.post), and points the modeling-guide cue and the example at that anchor;
• says toggles author that return so Unlike stays on the parent page, and removes the separate-Create-page caveat;
• names the no-input exception in the associated-create return and entry-point passages of references/modeling-guide.md and references/foundation-plan-023.md;
• adds to the signed-in gate example that a guest is sent to sign in and returns to the page they asked for, which #1005 also ships;
• adds a one-tap-like-record eval expectation for destroy.return_to through Like's Recipe Association.

SKILL.md, references/interview.md, and the modeling guide's implementation-notes section are untouched, so this stays clear of skill-fit-check. The commit merges cleanly onto plugin-0-8-4.

Release: fold this into the 0.8.4 release branch plugin-0-8-4; do not release it on its own. It must publish only after firstdraft/firstdraft#1005 is merged and deployed and Pages republishes the Guide anchor. Version, CHANGELOG label, and plugin_source.tarball_sha256 are left for that branch, so hosted CI's pinned-CLI package step is expected to fail on the digest here (packed with pinned CLI 2f4bc93, this branch alone gives 1b0c167991c577925f6cea573f23d7633ab7f570a81255ac25ee3cbc76024966; the release branch repacks it). Local npm ci --ignore-scripts && npm audit && sh script/check passes (85 tests, 0 vulnerabilities), including the schema test that validates the copied Like fragment.

Proposed CHANGELOG bullet for the 0.8.4 entry:

- Records made by a tap, such as likes and follows, now match the Compiler's one-tap button: a tap creates the
  record and returns to the parent page. For a toggle, the Skill also authors `destroy.return_to` through the parent
  Reference, so Unlike returns to the parent page; without it, Unlike goes to the ordinary delete destination, such
  as Home. The Like example is a copy of the Foundation Plan Guide's
  [No-input records](https://firstdraft.github.io/firstdraft/docs/architecture/design/foundation-plan.html#no-input-records)
  example. An existing Plan with a Like/Unlike toggle can add the same `destroy.return_to`. The 0.8.3 note that the
  deployed Compiler may still show a separate Create page no longer applies. In an app where every page requires
  sign-in, a guest who opens a page is sent to sign in and returns to that page afterwards.

Docs: updated the Skill's modeling guide, examples, and Foundation Plan reference for one-tap records and guest sign-in; the CHANGELOG bullet above goes into the 0.8.4 release branch.

[raghubetina]

Superseded: shipped in plugin 0.8.4 through #125 (claude-v0.8.4, skills 450ea99), now npm latest and selected in the catalog.