feat(linkedin-studio): N13 — publiserings-slots + vacancy-varsel + WIP-roll-up + slot-default [skip-docs]

A1-10 + D-5. The queue answers "what is scheduled"; nothing answered "is the week
covered, and what is still being written". N13 makes both readable at session start.

- Publishing slots are operator config: profile/publishing-slots.json in the per-user
  data dir, schema + OPT-IN template in config/publishing-slots.template.json. The
  plugin ships no publishing times and writes the grid for nobody; absent config means
  every slot surface stays silent (same never-nag discipline as the trend/brain nudges).
  Data dir rather than the state file, which is machine-written and whose frontmatter
  reader does not parse lists.
- hooks/scripts/slots.mjs (new): one implementation behind four surfaces. Zero-dep (a
  SessionStart hook must not spawn tsx), pure core (dates in as strings, no clock),
  imported by the commands exactly as queue-manager.mjs already is — so session-start's
  vacancy warning and Step 10's slot default cannot drift apart.
- Coverage counts the short-form queue (scheduled/published; cancelled frees the slot)
  AND editions-register rows claiming that date, counted per date, so long-form and
  short-form cannot be double-booked and a two-slot day needs two posts.
- Session start gains "## Editions in Flight" (series, phase, next action, claimed slot,
  days in flight) and "## Publishing Slots" (next open slot, open count in 14 days, and
  how to fill it when the gap is <=3 days). The existing discovery nudge is untouched.
- /linkedin router + /linkedin:calendar surface the same roll-up; calendar documents the
  opt-in copy. /linkedin:newsletter Step 10 defaults to the next open slot (one
  confirmation, not an interview) and writes --slot onto the register row.
- D-5: references/scheduling-strategy.md marked "confidence: low / directional" per the
  algorithm reference's own standard, deferring to the operator's grid and their own
  analytics. Neutral example time replaces the operator-specific one in the N12 docs.

TDD: red proven first (module absent; 5 session-start behaviours failing).
hooks 140 -> 174 · test-runner 184 -> 197 (Section 16t: 13 unconditional greps incl. a
de-niche check that no publishing time is hardcoded in the slot path and no operator grid
is committed, + non-vacuity self-test; anti-erosion floor 166 -> 179).
Suites green: trends 300/0 · brain 134/0 · editions 72/0 · specifics-bank 45/0 ·
tests 35/0 · render 60/0.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QxvWAjte7vPcF79QeSRvRJ

commands/newsletter.md

@@ -2080,9 +2080,24 @@ now a first-class scheduled post.
 
 **Procedure:**
 
-1. **Pick the slot.** Confirm the target `scheduled_date` (YYYY-MM-DD) and
-   `scheduled_time` from the edition-config calendar / the series brief. If the
-   slot is unset, ask once (Step 1's calibration may already have settled it).
+1. **Pick the slot — default to the next open one (N13).** Read the operator's
+   publishing grid and take the first slot nothing covers yet, so scheduling is
+   one confirmation rather than an interview:
+
+   ```bash
+   node --input-type=module -e "
+   import { nextFreeSlot, formatSlot, readSlots } from '${CLAUDE_PLUGIN_ROOT}/hooks/scripts/slots.mjs';
+   const s = readSlots().slots.length ? nextFreeSlot({ days: 28 }) : null;
+   console.log(s ? s.date + ' ' + s.time + '  (' + formatSlot(s) + ')' : 'NO SLOT');
+   "
+   ```
+
+   Propose that date/time and ask **once** for a yes/no. `NO SLOT` means the grid
+   is unconfigured or every slot in the next 28 days is taken — then fall back to
+   the edition-config calendar / series brief, and ask for the slot outright
+   (Step 1's calibration may already have settled it). A slot the operator
+   overrides is simply used as given; the default is a starting point, never a
+   constraint.
 
 2. **Register via `queue-manager.mjs`.** Add one queue entry for the edition,
    reusing the short-form queue contract — `queueAdd(id, draftPath, schedDate,
@@ -2119,9 +2134,12 @@ now a first-class scheduled post.
    `edition-state.json`. Write a closing "edition scheduled → mark live via
    `/linkedin:calendar` on <date>" line to `<serie>/STATE.md` (overwrite). The
    pipeline is complete.
-   **↳ Phase transition** — run the protocol (Step 0) for `scheduling`,
-   `--next "published — mark live via /linkedin:calendar"`, and then **close the
-   register row** (this step alone does):
+   **↳ Phase transition** — run the protocol (Step 0) for `scheduling`, this time
+   **with the slot** (`--slot "<YYYY-MM-DD HH:MM>"`, the one confirmed in step 1)
+   and `--next "published — mark live via /linkedin:calendar"`. The slot on the row
+   is what makes the edition visible as *coverage* of that publishing slot, so the
+   next session stops offering it as open. Then **close the register row** (this
+   step alone does):
 
    ```bash
    node --import tsx "${CLAUDE_PLUGIN_ROOT}/scripts/editions/src/cli.ts" register-complete \
@@ -2214,6 +2232,7 @@ the honest decision surface; it sells nothing.
 - `${CLAUDE_PLUGIN_ROOT}/config/edition-state.template.json` — edition-state schema (18 phases including Fix #2 lived-specifics extraction (Step 1.5) + `articles.NN.livedSpecifics`, the deterministic §B/§C1 contract-gate (Step 4.5), v2.1 skeleton + spine-prose gates, v2.3 visual-assets, v2.4 editorial-review, and v3.1 headless-review + per-article `personas` + `pivots`)
 - `${CLAUDE_PLUGIN_ROOT}/scripts/specifics-bank/` — lived-specifics store + per-edition binding (Fix #2, kilde-så-draft): `query`/`add` (Step 1.5), `validate-binding` (Step 2.5 gate), `render-kilder` (`NN-kilder.md` ledger), `record-usage` (Step 8 lock — «used in edition NN»). Design record: `docs/fix2/slice2-binding.md`
 - `${CLAUDE_PLUGIN_ROOT}/scripts/editions/` — series-level memory (N11): `distil-append` writes what a locked edition spent to `<serie>/linkedin/series-distillate.json` (Step 8), `distil-check` gates the next skeleton against it (Step 2.5). Deterministic character-trigram similarity; advisory, never blocking. **Editions register (N12):** `register-upsert` at every phase transition (appends `articles.NN.phaseLog` + mirrors the row into `${LINKEDIN_STUDIO_DATA:-$HOME/.claude/linkedin-studio}/editions/register.json`), `register-list` for the work-in-progress view, `register-complete` at Step 10 (measured lead time). The register mirrors state — resumption never reads it
+- `${CLAUDE_PLUGIN_ROOT}/hooks/scripts/slots.mjs` — the publishing grid (N13): `nextFreeSlot` gives Step 10 its default slot (queue + register coverage), and session start reports open slots from the same functions. Zero-dep, so hook and command can never disagree. The grid itself is operator config (`${LINKEDIN_STUDIO_DATA:-$HOME/.claude/linkedin-studio}/profile/publishing-slots.json`); unconfigured means Step 10 simply asks
 - `${CLAUDE_PLUGIN_ROOT}/config/edition-config.template.json` — static delivery metadata schema (calendar, freshness, credit, captions) — Step 8
 - `${CLAUDE_PLUGIN_ROOT}/config/image-credit-caption.template.md` — cover motif + credit + caption table (honest-about-AI credit) — Step 7.5
 - `${CLAUDE_PLUGIN_ROOT}/config/edition-delingstekst.template.md` — distribution-copy grammar (`## Del N —` / `## Samle`) — Steps 8/9