feat(linkedin-studio): SB-S3c — cross-silo id-threading + post→analytics assembler [skip-docs]

Hub-side design: the published record now carries the specifics/trends ids
it was built from (additive, omit-empty → byte-backward-compatible), and a
new pure assembler (scripts/brain/src/assemble.ts + `brain assemble`) joins
post↔analytics by normalized title-prefix + date with honest confidence
tiers (high/low/none). Answers the arc's north-star query: which raw
material actually performs? (specific → post → measured analytics).

All four tributaries untouched (analytics READ-only via inlined raw-JSON,
no package import); profile.md grammar untouched (the fact→post link stays
OUT — C-1). The repeatable --specific/--trend ingest flags collect via a
new collectRepeated helper, leaving parseFlags untouched.

TDD: 19 new brain tests (ingest 4 + publish 3 + assemble 8 + cli 4), all
SC1–SC12. brain 113/113, gate 95/0/0, BRAIN_TESTS_FLOOR 94→113,
ASSERT_BASELINE_FLOOR unchanged at 80. Light-Voyage hardened
(brief-review 5 FIX · plan-critic 1 BLOCK+4 MAJOR+4 MINOR · scope-guardian ALIGNED).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RigJBiRFNtFZKCz21qNbQ4

docs/second-brain/architecture.md

@@ -77,7 +77,7 @@ Run on a cadence (reuse the existing session-start staleness-nudge surface) as a
 | **SB-S0 — Foundation** ✅ *landed 2026-06-23* | `brain/` scaffold + two-layer `profile.md` (fold in `user-profile.md`) + `index.md` MOC + `operations.md` + `journal/`; entity-id + provenance shape as a small typed, tested module; `ingest/` dirs + manual-import contract. **No loop yet.** Shipped as `scripts/brain/` (TS, 34 tests, gate-wired BRAIN floor); fold = P1 labeled-scalars + P2 expertise (checkbox-prefs deferred, §8 of `plan-sb-s0.md`). | Smallest thing that stands up and is testable; locks the id/provenance spine everything hangs on |
 | **SB-S1 — Ingest + gold signal** ✅ *landed 2026-06-23* | Manual import → `ingest/published/` with `provenance=published` (CLI `brain ingest`); voice-trainer wired to learn from published-only, never `ai-draft`, gate-enforced. Shipped as `scripts/brain/src/ingest.ts` + `docs/second-brain/ingest-manual-import.md` (v0.5.1). **No profile.md mutation** (SB-S2). | The gold signal before the loop that consumes it |
 | **SB-S2 — Evolution loop** ✅ *landed 2026-06-23* | Operator-invoked, operator-gated consolidation: `brain consolidate` (`--gather`/`--propose`/`--apply --confirm`) → profile **diff** w/ evidence_count/provenance/timestamps; threshold-promotion (N=3); contradiction → keep-both with distinct ids (no supersede); decay-flag (90d); `consolidation-state.json` sidecar; zero-dep session-start consolidation-due nudge + scaffold-ensure. Shipped as `scripts/brain/src/consolidate.ts` + `docs/second-brain/consolidation-loop.md` (v0.5.2). **Operator decisions:** journal deferred · no new agent (session extracts) · motor-only (no reader until S3). | The compounding mechanism |
-| **SB-S3 — Cross-silo graph + ops centre** | Thread the id through tributaries (post↔specific↔trend↔analytics assemblable); flesh out `operations.md`; retire the dead `content-history.md` + triple-post reconciliation | Finally answers "which raw material performs?" |
+| **SB-S3 — Cross-silo graph + ops centre** | Thread the id through tributaries (post↔specific↔trend↔analytics assemblable); flesh out `operations.md`; retire the dead `content-history.md` + triple-post reconciliation. **S3a ✅ first reader · S3b ✅ supersede · S3c ✅ cross-silo id-threading** (hub-side: the published record carries the `specifics`/`trends` ids it was built from + a pure analytics resolver — `scripts/brain/src/assemble.ts`, `brain assemble`; tributaries untouched). **S3d remains** (ops centre / `content-history.md` retirement / triple-post reconciliation). | Finally answers "which raw material performs?" |
 | *(later / optional)* **SB-S4** | EU/EEA DMA portability API as an auto-tributary into `ingest/inbox/` | Additive; never a dependency |
 
 ## What's genuinely hard (honest flags)