[justaugustus]

What kind of change does this PR introduce?

An OpenSpec proposal plus the first step of the refactor it plans (infra/tests/other). No change to scores, findings,
or output.

• PR title follows the guidelines defined in our pull request documentation

What is the current behavior?

Each check's wiring is written twice: once in the check's own function, and again in probe mode's 20-case
assignRawData switch, which carries a nolint:gocognit,gocyclo. Nothing keeps the two in step. #5425 added check
definitions and moved Maintained and CI-Tests onto them, with differential tests against the old bodies.

What is the new behavior (if this is a feature change)?

Behavior is unchanged. This PR has two commits:

1. openspec/changes/consolidate-check-definitions/ plans the rest of the work. The other 18 checks move to
   definitions in batches. Probe mode reads the same definitions, so assignRawData goes. The check registry
   (names, request types, experimental gating) is built from the definitions. Consistency tests guarantee one
   definition per check and a collector for every check a probe needs. The spec deltas record two current
   behaviors as tested requirements: checks and probes collect the same raw data, and every check a registered
   probe needs is a registered check.
2. Step 1 of that plan. The pilot's definition code moves from checks to internal/checkdef, so
   pkg/scorecard can read it later without new exported API. A check runs as checkdef.Maintained.Run(c). The
   exported checks.Maintained and checks.CITests keep their signatures.

• Tests for the changes have been added (for bug fixes/features)

Step 1 is a move. The differential tests from #5425 cover it unchanged.

Which issue(s) this PR fixes

NONE

Special notes for your reviewer

Main question: is this the plan you want before more checks move? The decisions most worth a second opinion are
in design.md:

• Packaging stays two-mode (D3). The check merges the GitHub and GitLab collectors on a local directory and
  returns empty data on other hosts. Probe mode supports only GitHub and GitLab and errors elsewhere. Phase 2 keeps
  both behaviors through a separate probe-mode collector. Unifying them would change --probes output, so it's left
  for its own change.
• Definitions live in an internal package (D1), not behind an exported accessor in checks. An accessor would be
  permanent public API for an implementation detail.
• The registry moves in this change (D4). GetAll and GetAllWithExperimental keep their signatures and
  results, guarded by a snapshot test taken before the switch.

Out of scope: the CI-Tests output order and the duplicate check-name constants noted in #5425. Both stay as they
are; the plan adds a consistency test that pins the constants.

Verification beyond CI:

• openspec validate consolidate-check-definitions --strict passes.
• For step 1, I set CI-Tests' definition to the Maintained name, and TestCITestsDefinitionMatchesLegacy failed.
  That shows the differential tests exercise the moved code.

Rollback: revert the second commit. The first commit adds only the OpenSpec change.

Does this PR introduce a user-facing change?

NONE

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.68%. Comparing base (353ed60) to head (91d6df4).
⚠️ Report is 468 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5427       +/-   ##
===========================================
+ Coverage   66.80%   79.68%   +12.87%     
===========================================
  Files         230      264       +34     
  Lines       16602    14900     -1702     
===========================================
+ Hits        11091    11873      +782     
+ Misses       4808     3026     -1782     
+ Partials      703        1      -702     

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