refactor(#1992): move the transpiler under src/cnx/

[devin-ai-integration]

Summary

src/ now holds cnx/, the transpiler (PARSE/, TRANSPILE/, WRITE/, types/, utils/, instrumentation/). Its consumers cli/ and lib/ sit beside it. This is the owner's direction on #1313 (2026-10-11). Generated output is unchanged: no fixture .expected.* file changed, and Integration Tests and Verify Clean both pass.

Changes

• Modified: scripts/move-modules/MOVES.ts - adds six root entries (src/<root> → src/cnx/<root>), applied with npm run move:modules -- --apply. That moved 1034 .ts files and rewrote their importers. I moved the 2 oracle .h fixtures with git mv. 4 vi.mock specifiers in cli/ and lib/ tests were rewritten by hand.
• Regenerated: the ANTLR output under src/cnx/PARSE/2-Parse/**/grammar/, with npm run antlr:all. The mover had stripped .js from its imports. The regenerated files are byte-identical to main's. The mover defect is filed as move:modules rewrites imports inside generated ANTLR output #2009.
• Modified: docs/architecture/README.md §1 - the tree now draws src/cnx/ with the layers and shared roots, and cli/ and lib/ beside it. The "four kinds" paragraph says the hosts sit beside cnx/ and that nothing in cnx/ imports them.
• Modified: scripts/layout/Layout.ts - a layer is now a drawn directory with no drawn subdirectory of its own. That makes cnx/ a container rather than a layer, and only layers may hold __tests__/.
• Modified: .dependency-cruiser.cjs - every path rule now names ^src/cnx/. The new transpiler-imports-no-host rule forbids ^src/cnx/ → ^src/(cli|lib)/. Tests are not exempt (owner ruling on box 4). The rule is reachable: true, and a named assertion in layer-rules.test.ts keeps it that way.
• Moved: 71 tests and helpers under src/cnx/ that reach the host (Transpiler, TargetCatalogFile, TargetResolver, MockFileSystem, parseCHeader, JsonCodec) to src/cli/__tests__/cnx/, mirroring their old paths. Composing passes is the host's job (layout: src/ becomes the pass table — destination map first, cleanup PRs, then the move #1443). codeGenSymbolsHelpers, enterScope and installMockSymbols name only transpiler modules, so they move into cnx/ instead. Each move is recorded in MOVES.ts.
• Deleted: docs/coverage/, a stale generated coverage report. CI publishes coverage to Pages, so nothing reads it. Its .gitignore and .cspell.json entries are gone too.
• Modified: scripts/plan-render-state/PlanRenderState.ts - placeOf names the layer, not cnx/.
• Modified: tests that build paths: the repo-root depth for tests under cnx/, join("src", "cnx", …) segments, and the artifact-lifetime regexes.
• Modified: package.json (antlr and clean paths), knip.json, vitest.config.ts, .oxlintrc.json, sonar-project.properties, .github/workflows/pr-checks.yml, the prettier-plugin/ imports, 2 tests/regression scripts, the scripts/ gates, docs, AGENTS.md, CLAUDE.md, and .claude/skills/issue-check.
• Modified: scripts/__tests__/layout.test.ts - adds cases for a shared root put back beside cnx/, a layer outside cnx/, and a bare file or __tests__/ in cnx/.

Pre-Submit Checklist

Code Quality

• Code is properly formatted
• No oxlint errors in modified files (CI Static Analysis)
• TypeScript compiles without errors
• All tests pass (CI: Unit, Integration, CLI, Verify Clean)

Documentation

• README.md updated (architecture README §1)
• ADR updated with implementation details (n/a)
• learn-cnext-in-y-minutes.md updated (n/a, no syntax change)
• Test README created (n/a)

Git Hygiene

• Only related files included
• No debug code left in source
• Commit messages are descriptive

Testing

Mutation checks. I restored the tree after each one, and the gate went green again:

• mv src/cnx/types src/types: layout:check exits 1 with 2 failures (missing cnx/types/, unexpected types/).
• mv src/cnx/WRITE src/WRITE: layout:check exits 1 with 3 failures.
• Adding import "../3-Render/MisraSuppressionUtils" to 2-Plan/EmissionPlan.ts: depcruise reports error 2-2-plan-reads-no-later-pass.
• Adding import "../../../cli/TargetResolver" to 1-Discover/NodeFileSystem.ts: depcruise reports error transpiler-imports-no-host. The clean tree has 0 errors.
• scripts/__tests__/layout.test.ts: 26/26 pass.

SonarCloud: 0 open issues on the PR, and the gate is OK.

Still open on #1992:

• Box 4: no file under src/cnx/, tests included, imports src/cli/ or src/lib/. depcruise reports 0 errors. Adding a cli/TargetResolver import to a cnx/ test makes transpiler-imports-no-host fail.
• Box 5: no current file names an old path. History is left out by owner ruling: MOVES.ts, released CHANGELOG.md entries, docs/plans/, docs/archive/.

Related Issues

Closes #1992. Part of #1313. Found here: #2009.

Link to Devin session: https://app.devin.ai/sessions/f8dad7b6b64443cd859a9c5715f51417
Open in Devin Desktop: https://app.devin.ai/desktop/session/f8dad7b6b64443cd859a9c5715f51417?variant=devin
Requested by: @jlaustill

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[jlaustill]

Review Summary

PR: #2007 (refactor(#1992): move the transpiler under src/cnx/)
Reviewed by: Claude (automated review)

Overview

The move itself checks out. In a clean clone at 605f7a50, npx tsc --noEmit, typecheck:scripts, depcruise (0 errors) and layout:check all pass. CI unit counts went from 428 files / 8503 tests (base 1a3f0b1a) to 428 / 8507 (this head), so no test was lost. No .expected.* file changed. A grep for src/(PARSE|TRANSPILE|WRITE|types|utils|instrumentation) outside the history exclusions finds nothing. At 2026-10-11T20:53Z the head had 31 check runs passed, 2 skipped (Deploy Coverage), and 0 open Sonar issues. The findings are about the new guard's strength and about prose the rewrite made false.

Findings

Severity	Count
Critical	0
Important	1
Moderate	3
Nit	2

Key Issues

• transpiler-imports-no-host matches direct edges only. In a mutation test, a cnx/ test that reaches cli/TargetResolver through a scripts/ module passed at 0 errors. reachable: true catches it (2 errors) and leaves the clean tree at 0. layer-rules.test.ts cannot hold the keyword through LAYER_ROOTS without sweeping in collectors-build-names-from-scopes (measured), so the rule needs a named assertion.
• History narration was rewritten to the new paths. About 18 lines now say things like "#1444 moved the port into src/cnx/PARSE/1-Discover/". The inline comment lists each one. Writing them relative to the layer keeps them true and keeps box 5's grep clean.
• Test-placement docs. CLAUDE.md:679 says both analyzer helpers live in cnx/, and one moved to cli/. CLAUDE.md:737 and Layout.ts:14 say tests sit beside their module, which no longer holds for 71 files, and nothing records where they went.

What Looks Good

• Every move is in MOVES.ts with a reason (80 entries), so the move can be rerun on a fresh main and reviewed in the diff.
• The mover defect that Verify Clean caught was filed as #2009 instead of being worked around silently, and the grammar was regenerated rather than edited.
• layout.test.ts adds cases for each new failure mode: a shared root put back beside cnx/, a layer outside cnx/, and a bare file or __tests__/ directly in cnx/. A README tree mutation (drawing a pass's subdirectory) also fails loudly (20 failures), so the new layers() definition does not hide a misdrawn tree.

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🤖 Automated review by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
94.3% Coverage on New Code
0.1% Duplication on New Code

See analysis details on SonarQube Cloud