feat(linkedin-studio): SB-S3e — retire dead content-history + read-side brain reconcile [skip-docs]

The LAST second-brain slice; the S0–S3e arc is now complete.

(b) Retire the dead, zero-reader content-history.md across its 8 plumbing
surfaces: the flaky Stop-hook writer prose, the template (git-rm'd), the
migrate-data.mjs B1 MOVE entry + its test assertions, .gitignore, the gate
SC2_CLASSES guard, the data-path ref-doc, and a session-start comment. SC1
grep = 0; migrate suite 5/5 (R8 idempotency demonstrated).

(c) `brain reconcile` — read-side triple-post reconciliation joining silo 1
(## Recent Posts, auto-tracked creation) to the silo 2↔3 graph, surfacing the
coverage gap: posts created via the plugin but never `brain ingest`-ed. New
pure core scripts/brain/src/reconcile.ts (parseRecentPosts tracks the WRITER
format state-updater.mjs:116, NOT the date-only pruner; reconcileRecentPosts
matches hook→record.body→graph for the in-graph/in-brain-only/orphaned tiers;
loadRecentPosts reads STATE_FILE via the canonical getStateFile() chain — a new
cross-seam read, the state file lives outside the brain dataRoot). Wired as the
`brain reconcile` CLI subcommand (inline parsePublishedRecord loader, not the
body-less listPublished). Read-only: never writes the state silo.

Tests (verified live): gate 99/0/0 (ASSERT floor 82→84; new Section 16f
self-test + CLI grep) · brain 127/127 (floor 114→127, +13 reconcile) · hook
suite 136/136. SC4/SC6 end-to-end run is a real behavioural pass (STATE_FILE
seam read + fallback). Honest limit: read-side cannot reconstruct un-captured
specifics/trends — auto-capture is the flagged follow-up.

Brief/plan: docs/second-brain/{brief,plan}-sb-s3e.md (fbad29d). Go-before-code
gate cleared (operator: retire · read-side · build-now).

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

hooks/prompts/state-update-reminder.md

@@ -63,23 +63,3 @@ If a LinkedIn post was created or finalized in this session, save the full post
 - **Ask the user for confirmation** before writing: "I'll save this post as a voice sample for drift detection. OK?"
 - This builds the voice sample library that enables automatic drift scoring (needs 5+ samples for reliable scoring)
 - The more samples collected, the more accurate the voice-trainer's drift detection becomes
-
-**5. Content History Log** (if a post was created)
-
-If a LinkedIn post was created or finalized, append an entry to the content history log:
-
-- If `${LINKEDIN_STUDIO_DATA:-$HOME/.claude/linkedin-studio}/analytics/content-history.md` does not exist, initialize it from `config/content-history.template.md`
-- Append a new row to the "## Content Log" table:
-  ```
-  | YYYY-MM-DD | "Hook text..." | topic_area | format | word_count | char_count | source |
-  ```
-  Where:
-  - `date`: Today's date
-  - `hook`: First 60 characters of the hook line
-  - `topic`: Matching expertise_area value (for pillar tracking)
-  - `format`: post/quick/react/video/pipeline
-  - `word_count`: Word count of the full post
-  - `char_count`: Character count of the full post
-  - `source`: original/url/curated (where the idea came from)
-- This is append-only — never edit or delete existing entries
-- This log enables `/linkedin:report` and `analytics-interpreter` to track content production over time without requiring LinkedIn CSV imports