Phase 1.5: consolidateConcepts fails — named graph not bootstrapped #525

Symptom

First consolidateConcepts cron run after the 48h DEV soak (#448) failed:

2026-06-21 03:47 UTC consolidateConcepts FAILED (duration 7.4s)

transaction rolled back by an internal error:
  "AC9753D6C4764F5ABE3B3CA4E88233C0"."(DO statement)":
  line 4 col 3 (at pos 129): generic. Error -
  https://developers.sap.com/kg/tutorials: Object does not exist
  or is inaccessible

GraphMetadata row was never inserted (still 0 rows post-soak).

Root cause (hypothesis)

The consolidator issues a SPARQL INSERT DATA { GRAPH <https://developers.sap.com/kg/tutorials> { ... } } against the named graph defined in srv/lib/kg-graph-rebuild.js:35 as DEFAULT_GRAPH_IRI. HANA Cloud's SPARQL engine rejects the insert because the graph object hasn't been created yet — it doesn't auto-create on first INSERT.

Fix options

1. Pre-create on first run: issue CREATE GRAPH <https://developers.sap.com/kg/tutorials> (or CREATE SILENT GRAPH ... if idempotent) before the first INSERT DATA. Wrap in a transaction guard so re-runs after first success are no-ops.
2. Lazy create-or-skip: catch the "does not exist" error code on first INSERT, issue a CREATE, retry. Inverts the order but is more failure-tolerant.
3. Bootstrap script: a one-shot CLI (sibling of npm run kg:reextract) that issues the CREATE GRAPH. Avoids changing the consolidator. Trade-off: needs to be remembered before each new HDI container.

Likely option (1) since it's most robust against fresh QA / future PROD provisioning.

Impact while open

• DEV sidebar shows nothing on every tutorial OP (hide-on-empty short-circuits before the sidebar mounts visibly)
• Telemetry: zero kg.* events recorded during 48h soak (no sidebar → no events)
• Concept extraction is unaffected — 1089 ACTIVE concepts + 2183 TutorialConceptLinks + 569 ConceptEdges are still being curated by the nightly extractConcepts cron

Repro

# Hits the same failure mode on demand:
cf run-task tutorials-srv -c "node -e 'import(\"@sap/cds\").then(({default:cds})=>cds.connect.to(\"db\").then(async d=>{ const r = await d.run(\"SPARQL INSERT DATA { GRAPH <https://developers.sap.com/kg/tutorials> { <urn:test> <urn:p> <urn:o> . } }\").catch(e=>e.message); console.log(r); process.exit(0); }))'"

Or just wait for the next scheduled consolidateConcepts Sunday 03:47 UTC.

Refs

• Knowledge graph of related tutorials and to help with learning discovery #381 (KG epic)
• docs(kg): Phase 1 DEV rollout note (#381 PR 8/8) #442 (PR 7 — Vue sidebar that depends on this graph)
• Fill in Phase 1 rollout-note placeholders after 48h soak #448 (Phase 1 rollout note post-soak fill-in — surfaced this)
• srv/lib/kg-graph-rebuild.js:35 (DEFAULT_GRAPH_IRI)
• srv/lib/kg-queries.js:240 (FROM <…> clause)
• srv/jobs/scheduler.js:188-199 (cron registration)