## Summary
Turns the audit-log table's `trace_id` and `actor_id_hash` columns from inert text into the two pivots an investigator actually needs:
- **trace_id** → Jaeger deep link (opens in a new tab). Closes the "join audit + traces by trace_id" loop from [ADR-0012](docs/decisions/0012-observability-pino-opentelemetry.md) / [ADR-0013](docs/decisions/0013-audit-trail-separated-postgres-append-only.md) without any new BFF surface.
- **actor_id_hash** → click to refilter the table on that single actor. "Show me everything else this user did" stays in the page; no copy-paste loop.
## What lands
### Trace-id deep link to Jaeger
[`audit.html`](apps/portal-admin/src/app/pages/audit/audit.html#L162-L173) — the cell becomes an `<a target="_blank" rel="noopener noreferrer">` pointing at `${environment.jaegerBaseUrl}/trace/<traceId>`. Anonymous events (`traceId === null`) keep the dash placeholder.
[`environment.ts`](apps/portal-admin/src/environments/environment.ts) gains `jaegerBaseUrl`. Dev defaults to `http://localhost:16686` (matches the compose `observability` profile from `infra/local/dev.compose.yml`). Per-env replacement picks up whatever trace backend the future infrastructure ADR settles on — Tempo, Grafana Cloud, on-prem Jaeger; the SPA-side wiring doesn't care.
### Actor-pivot click
[`audit.html`](apps/portal-admin/src/app/pages/audit/audit.html#L146-L160) — non-null `actorIdHash` becomes a `<button>` styled to read inline like the hash text (`.actor-hash--clickable`: button reset + dotted-underline hover + brand-colored focus ring). Click → `filterByActor(hash)` sets the existing `actorIdHash` filter signal, resets offset to 0, and re-runs the query. Each pivot still emits its own `admin.audit.query` audit row server-side (per [ADR-0020](docs/decisions/0020-portal-admin-app.md)) so the drill is itself auditable.
Anonymous rows keep the `(anonymous)` plain-text rendering — there's no useful filter value to pivot on.
## Why not inline-expand Pino log lines under the row
Considered, deferred. The BFF's Pino output goes to **stdout only** today; standing up a queryable log aggregator (Loki, OpenSearch, …) is a separate infrastructure chantier with its own ADR. The Jaeger jump-off carries ~99 % of the investigator's needs anyway — the trace already contains span attributes (`db.statement`, `http.status_code`, exception events) for the same request scope; Pino lines on top of that would be redundant for most investigations.
When the log aggregator does land, the inline-expand model can come back as a follow-up: `GET /api/admin/logs?traceId=<id>` + an expand affordance on the same row. The current Jaeger anchor and the future inline-logs would naturally coexist (different drills, both surfaced on the same `trace_id`).
## Notes for the reviewer
- **Why a `<button>` for the actor cell rather than an `<a>`?** The action is an in-page filter change, not a navigation. Buttons keep keyboard activation (Enter / Space), don't pollute browser history, and screen readers announce "Filter the table on hash(jane), button" rather than a misleading link role.
- **Why the dotted-underline hover for the actor, but solid-underline for trace?** Different affordances. The trace anchor is a permanent link to an external resource (Jaeger UI), so the solid underline matches the universal "link" convention. The actor button is an inline pivot that *mutates state* — the dotted underline + hover-fill conveys "this does something subtle within the page" without screaming "link".
- **CSS guardrails preserved**: focus rings on both elements, brand-color tokens (light + dark), tap targets meet the AAA 44×44 minimum (the button reset preserves the line-height + the `cell-actor` padding ≥ 12 px on each side).
- **No new i18n strings.** `title` attributes are hover hints, not screen-reader-essential — the underlying hash + traceId are the actual semantic content. The "(anonymous)" string and the dash placeholder were already in the template.
- **No BFF change.** This whole PR is SPA-side only. The audit endpoint already returns `traceId` and `actorIdHash` in every row.
## Test plan
- [x] `pnpm nx run-many -t lint test build --projects=portal-admin` — green.
- [x] **54 portal-admin specs pass** (was 50; +4 for the four new behaviours).
- [x] Lazy `audit` chunk: 18.26 → ~18.5 KB raw / 4.44 KB gzip — comfortably under the per-chunk budget.
- [ ] **Manual smoke**:
- Sign in to portal-admin with `Portal.Admin` → open `/audit`.
- Click any trace_id → new tab opens at `http://localhost:16686/trace/<id>` (assuming `./infra/local/dev.sh up observability` is running so Jaeger is up).
- Anonymous rows show `—` for trace, `(anonymous)` (plain text, not clickable) for actor.
- Click any non-anonymous actor hash → the table refreshes filtered on that hash, the "Actor id hash" filter input above shows the same value, page jumps to offset 0.
- Tab through a row: timestamp / event are plain text; outcome badge skipped (not interactive); actor button gets focus ring; trace link gets focus ring; payload `<details>` summary gets focus ring.
## Follow-ups (optional)
- When the log aggregator ADR lands, extend the trace cell to also offer an inline-expand of Pino lines for that trace. Jaeger anchor stays as the primary affordance.
- A similar treatment on the `/users` page (clicking a row's `oid` to "show me this user's audit trail") is the natural sibling. Defer until there's an investigator workflow that asks for it — premature otherwise.
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Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #166
julien
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