fix(scaffold): add plugins/ to layered directories

[waynesun09]

Summary

• Add plugins to LAYERED_DIRS in all 5 reusable workflows (code, review, triage, fix, retro)
• Add plugins to the inline prioritize workflow's sparse-checkout and both copy loops
• Add "plugins/" to the Go layeredDirs slice in scaffold.go
• Create customized/plugins/.gitkeep to match the pattern of other layered dirs
• Update scaffold tests (TestLayeredDirsNotInstalled, TestCustomizedDirsInstalled, TestFullsendRepoFilesExist)

Test plan

• go test ./internal/scaffold/ — all 34 tests pass
• make lint — passes
• Verify in a live run that plugins/gopls-lsp is present in the workspace after scaffold

Closes #1251

[github-actions]

Site preview

Preview: https://bd0a2d4b-site.fullsend-ai.workers.dev

Commit: 9cd2f9c903cdacbacdeabf984cfb0b66d25bc60d

[fullsend-ai-review]

Review

Findings

Medium

• [protected-path] .github/workflows/reusable-{code,fix,retro,review,triage}.yml — Five reusable workflow files under .github/ are modified. The PR links to issue scaffold: plugins/ directory not copied to workspace — harness validation fails #1251 and the description explains the rationale (bug fix for harness validation failure caused by plugins/ missing from LAYERED_DIRS). Human approval is always required for protected-path changes, regardless of context.

Previous run

Review

Findings

Medium

• [protected-path] .github/workflows/reusable-{code,fix,retro,review,triage}.yml — Five reusable workflow files under .github/ are modified. The PR links to issue scaffold: plugins/ directory not copied to workspace — harness validation fails #1251 and the description explains the rationale (bug fix for harness validation failure caused by plugins/ missing from LAYERED_DIRS). Human approval is always required for protected-path changes, regardless of context.

Low

• [docs-currency] docs/guides/dev/cli-internals.md:368 — The layered-directories table row lists agents/, skills/, harness/, policies/, scripts/, schemas/, env/ but is now missing plugins/. This is the only doc with a complete enumeration that was not updated by this PR (ADR 0035 and the user-facing customizing-agents guide were both updated).
  Remediation: Add plugins/ to the list on line 368 of cli-internals.md.

Previous run

Review

Findings

Medium

• [protected-path] .github/workflows/reusable-{code,fix,retro,review,triage}.yml — Five reusable workflow files under .github/ are modified. The PR links to issue scaffold: plugins/ directory not copied to workspace — harness validation fails #1251 and the description explains the rationale (bug fix for harness validation failure caused by plugins/ missing from LAYERED_DIRS). Human approval is always required for protected-path changes, regardless of context.

Low

• [docs-currency] docs/guides/dev/cli-internals.md:368 — The layered-directories table row lists agents/, skills/, harness/, policies/, scripts/, schemas/, env/ but is now missing plugins/. This is the only doc with a complete enumeration that was not updated by this PR (ADR 0035 and the user-facing customizing-agents guide were both updated).
  Remediation: Add plugins/ to the list on line 368 of cli-internals.md.

Previous run (2)

Review

Findings

Medium

• [protected-path] .github/workflows/reusable-{code,fix,retro,review,triage}.yml, internal/scaffold/fullsend-repo/.github/workflows/prioritize.yml — Six workflow files under .github/ (or scaffolded into .github/) are modified. The PR links to scaffold: plugins/ directory not copied to workspace — harness validation fails #1251 and the description clearly explains the rationale (adding plugins/ to LAYERED_DIRS to fix harness validation failure). Human approval is required for all protected-path changes regardless of context.

Low

• [consistency] internal/scaffold/fullsend-repo/scripts/post-review.sh, internal/scaffold/fullsend-repo/scripts/post-fix.sh — plugins/ is added to REVIEW_PROTECTED_PATHS in post-review.sh and PROTECTED_PATHS in post-fix.sh, but the corresponding protected paths list in .claude/skills/pr-review/SKILL.md is not updated. The skill definition notes these should be "kept in sync with post-review.sh".
  Remediation: Add "plugins/" to the protected paths list in .claude/skills/pr-review/SKILL.md.

• [docs-currency] docs/guides/user/customizing-agents.md:116-117 — The architecture diagram lists layered directories as agents/ skills/ schemas/ harness/ policies/ scripts/ env/ without plugins/. The guide already references plugins/gopls-lsp in harness config examples (lines 23-24, 257-258), but the layered-directory diagram is now incomplete.
  Remediation: Add plugins/ to the layered directories line in the architecture diagram.

Previous run (3)

Review

Findings

Medium

• [protected-path] .github/workflows/reusable-{code,fix,retro,review,triage}.yml — Five reusable workflow files under .github/ are modified. The PR links to scaffold: plugins/ directory not copied to workspace — harness validation fails #1251 and the description clearly explains the rationale (adding plugins/ to LAYERED_DIRS to fix harness validation failure). Human approval is required for all protected-path changes regardless of context.

Low

• [docs-currency] docs/ADRs/0035-layered-content-resolution.md — ADR 0035 enumerates layered directories in four places (lines 74, 88, 91, 101) as agents/, skills/, schemas/, harness/, policies/, scripts/, env/ without plugins/. Now that plugins/ is a layered directory, these lists are incomplete.
  Remediation: Add plugins/ to each enumeration of layered directories in ADR 0035.

• [docs-currency] docs/guides/user/customizing-agents.md:116-117 — The architecture diagram lists layered directories as agents/ skills/ schemas/ harness/ policies/ scripts/ env/ without plugins/. The guide already references plugins/gopls-lsp in harness config examples, but the layered-directory diagram is now incomplete.
  Remediation: Add plugins/ to the layered directories line in the architecture diagram.