add summary.md artefact to /council output

New Phase-5d step: the Moderator writes sessions/<slug>/summary.md
directly (no sub-agent), producing an 11-section readable summary —
TL;DR, winning answer verbatim, vote distribution with ASCII bar chart,
phrases that crystallized, per-member Phase-2-to-Phase-3 posture
shifts, confidence trajectory chart, influence map (positive-citation
counts), non-winning readings preserved as distinct lenses, watch
items flagged across multiple members, session mechanics stats, and
full artefact wikilinks.

outcome.md stays as the machine-structured record for the sessions
Base; summary.md is the artefact you actually reread a week later.
Phase-5f terminal output retires the full vote table in favour of a
one-line verdict, condensed ASCII vote chart, full winning answer,
and a pointer at summary.md.

CLAUDE.md and docs/structure/initial-plan.md updated to mention the
new file in the session directory layout.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/structure/initial-plan.md

@@ -139,7 +139,8 @@ council/                                   # ← repo root = Obsidian vault
         ├── initial-answers.md             # scribe: Phase 2 verbatim, attributed
         ├── revised-answers.md             # scribe: Phase 3 critiques + revised (round 1 + optional round 2)
         ├── votes.md                        # scribe: Phase 4 votes + tally
-        └── outcome.md                      # scribe: canonical session file (Obsidian Base target)
+        ├── outcome.md                      # scribe: canonical session file (Obsidian Base target)
+        └── summary.md                      # moderator: narrative summary with stats, influence map, phrases
 ```
 
 `.claude/` can be hidden in Obsidian's file-explorer settings; it doesn't break anything if visible. Wikilinks are folder-qualified (e.g. `[[members/vaasa/persona|Dr. Ingrid Vaasa]]`, `[[sessions/2026-04-19_self-host-email/outcome|Self-host email?]]`).