docs(examples): add IDEAS.md — backlog of creative example topologies

A sketch backlog of further examples, each teaching a distinct orchestration
topology (anthill/stigmergy, kitchen line/pipeline, incident room/blackboard,
senate/debate, baton/mutex+failover, immune system/reactive, evolution chamber,
plus ATC and day-night extras). Not implemented — ideas only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/IDEAS.md

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+# Example ideas — creative multi-agent topologies
+
+A backlog of *example* projects for `examples/`, each chosen to teach a **different orchestration
+topology** on the same harness. Nothing here is implemented yet — these are sketches.
+
+Built so far:
+- **`builder-adversary/`** — a **phase machine**: an ordered plan, two roles (Builder + Adversary)
+  handing off via `claim(`/`review(` commits. (The cc-ci pattern.)
+- **`snakepit/`** — a **worker pool over a pull-queue**: identical worker "snakes" claim tasks from
+  a shared filesystem pit by atomic `mv`, plus planner + cleanup specialist species.
+
+Each idea below lists: the metaphor, the topology it teaches, the star harness primitive, and what
+makes it distinct from what we already have.
+
+---
+
+## Strong candidates
+
+### 🐜 Anthill (stigmergy)
+Ants coordinate with *no direct messaging*: they lay pheromone trails, others follow the strong
+ones, and trails **evaporate** over time. Agents drop weighted "trail" files toward promising
+solutions/paths; a `[[service]]` slowly decays them.
+- **Teaches:** indirect coordination through a decaying shared environment (opposite of snakepit's
+  explicit claim).
+- **Star primitive:** a background **service** as the evaporation clock; emergent routing with zero
+  agent-to-agent chat.
+
+### 🍳 The Line (kitchen brigade)
+A restaurant pass: prep → sauté → plating → **expo**. A ticket (order) flows station to station; the
+expo bounces a bad plate back down the line. Many tickets in flight at once.
+- **Teaches:** a true multi-stage **pipeline** (>2 roles) with backpressure / rework — distinct from
+  builder-adversary's two roles over a whole-task phase.
+- **Star primitive:** chained `handoff` inboxes + per-station commit prefixes (`fire(`, `plate(`,
+  `expo(`).
+
+### 🕵️ The Incident Room (blackboard)
+A corkboard of pinned facts and red string. Specialist detectives (forensics, alibi, motive,
+witnesses) each watch the board and pin a new deduction *only when their preconditions appear*; a
+lead declares the case closed.
+- **Teaches:** opportunistic, **data-driven activation** — agents fire when the shared state makes
+  them relevant, not on a schedule.
+- **Star primitive:** a shared blackboard file + watchdog pings on board changes; no fixed order.
+
+### ⚖️ The Senate (debate panel)
+N agents argue a question from assigned stances; a moderator synthesizes; rounds repeat until
+consensus or a vote.
+- **Teaches:** structured **multi-round deliberation** with diverse "minds."
+- **Star primitive:** the **phase machine** where each phase = one debate round, plus **per-phase
+  model overrides** to give each seat a genuinely different model; `on_complete` writes the verdict.
+
+### 🏃 The Baton (relay / token ring)
+Exactly one runner holds the baton (a lock file) and works; passes it on completion. Drop the baton
+(crash) and the next runner picks it up.
+- **Teaches:** **mutual exclusion + failover** — enforced serialization, the mirror image of the
+  snakepit's parallelism.
+- **Star primitive:** `watch = "heal"` + the watchdog reaping a dead holder so the baton never gets
+  stuck.
+
+### 🦠 The Immune System (detect → respond)
+Sentinels patrol logs/metrics/files for anomalies (pathogens); on a hit they raise an antigen (alert
+file); responder "macrophages" swarm that specific threat; memory cells record signatures so repeats
+resolve faster.
+- **Teaches:** an **event-driven monitoring/reactive** topology with escalation.
+- **Star primitive:** a watcher **service** emitting alerts + reactive agents woken by inbox pings.
+- **Bonus:** genuinely *useful* — a self-healing "watch my repo/CI" tool wearing a fun costume.
+
+### 🧬 The Evolution Chamber (genetic algorithm)
+A population of candidate solutions; breeder agents mutate/crossbreed; a selector culls by fitness;
+generations advance until fitness plateaus.
+- **Teaches:** **population-based iterative search** with a fitness gate.
+- **Star primitive:** phase machine where each phase = one generation; `done_marker` trips when
+  fitness stops improving.
+
+---
+
+## Quick extras (less fleshed out)
+
+- **🗼 Air Traffic Control** — many workers contend for *one* scarce runway (a single deploy/build
+  slot); a controller grants timed landing slots. Teaches centralized **scarce-resource
+  arbitration** (snakepit has plentiful work; here the *resource* is the bottleneck).
+- **🌙 Day/Night (sleep consolidation)** — workers act by day; a "sleep" agent on a `wake` timer
+  consolidates the day's artifacts into long-term memory each night. Teaches **scheduled batch
+  consolidation** (the "memory builder / coprophagy" idea as its own example).
+
+---
+
+## Suggested next trio
+
+If picking three that cover the most new ground: **The Line** (pipeline), **The Incident Room**
+(blackboard), and **The Immune System** (reactive monitoring — and actually useful).
+
+Each should follow the snakepit shape: a README with the metaphor→compute mapping, an `agents.toml`,
+role prompts, and a tiny runnable task.