feat(council): add council advisory skill with parallel/sequential/debate flows

- 3 advisors (Pragmatist, Visionary, Skeptic) + 1 Referee subagent
- Default: parallel + synthesis flow
- Prompt templates in references/prompts.md
- Model tier selection based on topic complexity
- Added TODO tasks for personality depth and skill name revisit

skills/council/scripts/council.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# council.sh — Reference implementation for council orchestration.
+#
+# This script is NOT executed directly. It documents the orchestration
+# logic the main agent follows when invoking the council skill.
+#
+# The main agent uses sessions_spawn (mode=run) to create each subagent.
+#
+# ─── PARALLEL FLOW (default) ───────────────────────────────────────
+#
+# 1. Build advisor prompts from references/prompts.md templates.
+# 2. Spawn 3 advisor subagents simultaneously:
+#
+#    sessions_spawn(
+#      task = "<advisor system prompt>\n\nTopic: <topic>",
+#      mode = "run",
+#      label = "council-<role>",          # e.g. council-pragmatist
+#      model = "<chosen model tier>",     # optional override
+#    )
+#
+# 3. Wait for all 3 completion events (push-based).
+# 4. Collect advisor outputs.
+# 5. Spawn referee subagent:
+#
+#    sessions_spawn(
+#      task = "<referee system prompt with all advisor outputs>",
+#      mode = "run",
+#      label = "council-referee",
+#      model = "<chosen model tier>",     # may be stronger than advisors
+#    )
+#
+# 6. Deliver referee output to user with individual advisor perspectives
+#    included as collapsed summaries.
+#
+# ─── SEQUENTIAL FLOW ──────────────────────────────────────────────
+#
+# Same as parallel but advisors are spawned one at a time.
+# Each subsequent advisor sees prior outputs in their prompt.
+# Optional rebuttal round before referee.
+#
+# ─── DEBATE FLOW ──────────────────────────────────────────────────
+#
+# 1. Parallel initial takes (same as parallel flow steps 1-4).
+# 2. Rebuttal round: respawn each advisor with all other outputs visible.
+# 3. Collect rebuttals.
+# 4. Spawn referee with initial takes + rebuttals.
+#
+# ─── MODEL TIER SELECTION ─────────────────────────────────────────
+#
+# Light:  advisors=default, referee=default
+# Medium: advisors=default, referee=stronger (e.g. opus-tier)
+# Heavy:  advisors=stronger, referee=stronger
+#
+# The main agent decides tier before spawning based on topic complexity.