chore(concepts): retire legacy Hugo concept path + LEGACY_CONCEPT_RENDER (#1327 Task 6 Step 4)

.github/workflows/rebuild-content.yml

@@ -83,11 +83,6 @@ on:
         required: false
         type: boolean
         default: false
-      legacy-concept-render:
-        description: '#1327 escape hatch. Default (false): CAP renders /concepts/ list + detail pages server-side; the Hugo concept fetcher is skipped and publish-content calls the render-concepts phase. Set true to restore the legacy Hugo concept pipeline (fetch-concepts emits .md, publish-content walks hugo/public/concepts).'
-        required: false
-        type: boolean
-        default: false
 
 env:
   NODE_VERSION: '22'
@@ -387,24 +382,6 @@ jobs:
         env:
           CAP_BASE_URL: ${{ steps.srv.outputs.srv_url }}
 
-      # [Phase 3-A] Fetch published-concept payload from CAP and write
-      # one hugo/content/concepts/<slug>.md per published concept. Runs on
-      # `full` and `catalog-only`; skipped on `slug-targeted` (a single-tutorial
-      # rebuild does not need concept landing-page regeneration). The Hugo
-      # build picks up the new .md files in the subsequent build step.
-      # All other Phase 3-A wiring (classifier, kg.after hook, Hugo layout,
-      # publish-content concept support, AppRouter route, CAP serve handler)
-      # shipped in #685 — only this workflow invocation was missing.
-      - name: Fetch published concepts
-        if: ${{ steps.mode.outputs.effective_mode != 'slug-targeted' }}
-        run: npm run fetch-concepts
-        env:
-          CAP_BASE_URL: ${{ steps.srv.outputs.srv_url }}
-          # #1327 — fetch-concepts.ts self-guards: it early-exits unless
-          # LEGACY_CONCEPT_RENDER=true (default new pipeline renders concepts
-          # in CAP). Passing the input keeps the escape hatch one flag away.
-          LEGACY_CONCEPT_RENDER: ${{ inputs.legacy-concept-render == true && 'true' || 'false' }}
-
       # [#759] Homepage data feeds — homepage-shelves (60 link cards),
       # verb-definitions (6 verb tile back-faces), shelf-definitions
       # (4 shelf-header explainers). All three are read by Hugo at build
@@ -564,11 +541,6 @@ jobs:
           # other mode → whole-catalog delta, unchanged. TUTORIAL_SLUG is the
           # already-resolved slug (inputs.slug || dispatch_slug).
           PUBLISH_SLUG: ${{ steps.mode.outputs.effective_mode == 'slug-targeted' && (inputs.slug || steps.mode.outputs.dispatch_slug) || '' }}
-          # #1327 — drives publish-content's concept handling. Default (false):
-          # skip the hugo/public/concepts walk and call the render-concepts
-          # phase (CAP renders concept detail BLOBs). true: legacy Hugo walk,
-          # no render-concepts call.
-          LEGACY_CONCEPT_RENDER: ${{ inputs.legacy-concept-render == true && 'true' || 'false' }}
 
       # #1373 — synthetic watchdog. A green publish step is not proof rows
       # landed (the #1372 render-concepts 404 aborted AFTER an earlier

docs/developers/architecture/knowledge-graph.md

@@ -22,8 +22,11 @@ Each sub-phase adds one corpus with:
   and `renderMeta`.
 - A union extension in `hugo-apps/src/related-graph/types.ts` (`NodeType` +
   `OtherResource.type`).
-- A Hugo template section appended to `hugo/layouts/concepts/single.html`.
-- A frontmatter emission block in `scripts/fetch-concepts.ts`.
+- A `<section data-kg-section="…">` block in the concept detail template
+  `srv/lib/templates/concept-detail.ejs`, rendered server-side by CAP
+  (`srv/lib/concept-detail-render.js`) into the `concept-<slug>` BLOB. (The
+  legacy Hugo concept path — `hugo/layouts/concepts/single.html` +
+  `scripts/fetch-concepts.ts` — was retired in #1327.)
 
 ### Phase 4.1 — Learning journeys (#447)
 

docs/developers/operations/testing-endpoints.md

@@ -171,7 +171,7 @@ When `EXPOSE_CAP_UI=true` is set on the CAP srv app, these are accessible throug
 | `/build/slug-mapping` | GET | Slug→ID mapping for all missions/groups | None |
 | `/build/repo-catalog` | GET | Slug-keyed `DiscoveredTutorial` map (third-tier discovery fallback) | None |
 | `/build/repo-catalog` | POST | Write the discovered-tutorial baseline (CI-as-canonical-writer) | Bearer (`CONTENT_API_KEY`) |
-| `/build/concepts` | GET | Published Knowledge-Graph concepts (slug, name, description, teaches/requires/requiredBy/relatedTo). Consumed at build time by `scripts/fetch-concepts.ts`. | None |
+| `/build/concepts` | GET | Published Knowledge-Graph concepts (slug, name, description, teaches/requires/requiredBy/relatedTo). Shares `buildConceptsPayload` with the CAP concept-render pipeline (`GET /content/concepts-index` list page + the `POST /content/publish/render-concepts` detail phase, #1327). | None |
 | `/graph/publishConcept` | POST | Admin action — sets `publishedAt` + `publishedBy` on a Concept | XSUAA + `KnowledgeGraph.Admin` |
 | `/graph/unpublishConcept` | POST | Admin action — clears `publishedAt` + `publishedBy` on a Concept | XSUAA + `KnowledgeGraph.Admin` |
 | `/graph/explore-data` | GET | Bulk graph JSON for the `/explore/` page (nodes + edges + generatedAt; 5-min LRU cache) | None |

docs/superpowers/plans/2026-07-08-concepts-scale.md

@@ -607,7 +607,7 @@ Fetch payload once. Read shell fragments once (throw → whole phase fails: "she
 - [ ] **Step 1** Snapshot parity (**required PR check before Task 5 lands**): 10 hand-picked slugs (varied shapes) in the fixture. Fetch legacy Hugo output from DEV; render same slugs via new pipeline; diff allowing an explicit expected-diff list (render-source marker, `<script>` whitespace). Fail on unexpected diffs.
 - [ ] **Step 2** Smoke (`test/smoke/concepts-page.test.js`): `/concepts/` 200, `text/html`, gzip < 2MB, `#concepts-data` array of expected length, SSR `<li>` count == min(100,N), `/concepts/cap/` 200, cache headers, p50 cold < 200ms / warm < 30ms.
 - [ ] **Step 3** Load characterization (`hyperfine`, not a merge gate) — document p50/p95 in PR; block cutover if p95 cold > 300ms pending investigation.
-- [ ] **Step 4 (deferred, own PR)** After ~2 weeks DEV stability: delete legacy Hugo concept path + flag (~200 lines net deletion).
+- [x] **Step 4 (done, this PR)** Legacy Hugo concept path + `LEGACY_CONCEPT_RENDER` flag deleted after DEV+PROD stability confirmed (2026-08-09): removed `scripts/fetch-concepts.ts`, `hugo/layouts/concepts/{list,single}.html`, the `fetch-concepts` npm script + `build:all` reference, the workflow `legacy-concept-render` input + fetch step + publish env, and the `legacyConceptRender` branch in `publish-content.ts`.
 
 ---
 

hugo-apps/src/concepts-filter/main.ts

@@ -1,7 +1,8 @@
 // hugo-apps/src/concepts-filter/main.ts
 //
 // Mount point for the concepts filter island (#859). The island targets
-// the empty container Hugo emits in layouts/concepts/list.html —
+// the empty container CAP emits in the concept list page shell
+// (srv/lib/concept-list-page.js, #1327) —
 // `<div id="concepts-filter-controls" hidden>` — fills it in, and reveals
 // it. The rest of the page (grid, count, empty-state) is untouched by
 // this bootstrap and manipulated directly by App.vue's watcher.