[Duplicate] Feature/194 insights knowledge gaps

[Tanzkalmar35]

Important

Duplicate of #116

Related issue

#66

Short summary

Adds a knowledge-gaps panel backend in the insights module for project
managers: it surfaces components that are missing critical documentation
(runbooks/ADRs), ranked by severity, backed by a rebuildable cache of AI-classified
gaps.

• PM knowledge-gaps endpoints (new insights feature)
  • Entities KnowledgeGap (+ KnowledgeGapSeverity enum with lowercase api
    mapping); missingTypes/presentTypes as free-form strings; tables via ddl-auto.
  • KnowledgeGapsAiClient: outbound pull to the AI service
    POST /api/v1/insights/knowledge-gaps/detect (mirrors ChatAiClient). The AI
    owns detection and sources artifacts from its own index, so no data is sent.
  • KnowledgeGapsService: cached reads (read-only tx, sorted by severity then
    component/related items); refresh replaces the cache from the AI result.
  • KnowledgeGapsController (PM/ADMIN only):
    • GET /api/v1/insights/knowledge-gaps — overview, most severe first
    • GET /api/v1/insights/knowledge-gaps/{gapId} — detail (404 if missing)
    • POST /api/v1/insights/knowledge-gaps/refresh — trigger AI classification
  • Distinct class/file names from the FAQ feature (#181) to keep branch merges clean.
• Aligned with the real AI contract
  • AI response now carries presentTypes and drops owners/related-question count, matching the AI /insights/knowledge-gaps/detect endpoint (the index holds no user/ownership or question-history data). Mapper/service/tests updated.
• Component ownership (backend-owned, independent of the AI cache)
  • ComponentOwner entity + repository (component → userId).
  • Owners resolved at read time: a gap's component is matched to the ownership
    mapping and users resolved via the user module (UserApi); the owner's role is
    derived from the user's first project role. Refresh leaves ownership intact.
  • Endpoints (PM/ADMIN): GET/PUT /insights/knowledge-gaps/component-owners.
• Ingestion/analysis timestamps
  • Response now exposes lastIngested (renamed from lastUpdated),
    firstIngested and refreshedAt, so the UI can distinguish "first/last
    ingested" from "last analyzed".
  • New read-only ingestion-module API (ArtifactIngestionApi) resolves a
    component's first-ingested time as MIN(ingestedAt) over its artifacts
    (stable across re-ingestion). Purely additive — no change to the ingestion
    write path.

Checks

• I verified the code makes sense intuitively
• The PR changes affect only this issue, no unrelated/unwanted code changes to other modules/code segments
• CI runs (./gradlew clean build, keycloack)
• New business logic is unit tested, including WebMvcTest for api controllers
• The new functionality is tested manually

Additional notes

• Architecture: cross-module access stays explicit via exported module APIs
  (UserApi, new ArtifactIngestionApi) — no direct repository access across
  modules. The insights module stays loosely coupled.
• The AI service is stateless and pull-based: the backend triggers detection and
  caches the result; the cache is fully rebuildable via the refresh endpoint, and
  component ownership survives refreshes.
• Severity is rendered lowercase in the API; owner id exposes the upstream user
  reference and the owner DTO surfaces the project role.
• Test coverage: controller slice tests (401/403/404/200, including
  @PreAuthorize on the coroutine endpoint via async dispatch) plus service unit
  tests for detection caching, owner enrichment/set, and timestamp resolution.
  detekt clean.
• Contains a small follow-up "klint fix" commit for a detekt/lint issue in
  KnowledgeGapsAiException.
• Builds on Feature/181 insights faq #115 (pull-based AI insights) and shares the insights module with the
  FAQ feature (#181).