docs(examples): add builder-solo — single builder, no adversary (control)

A single Builder that builds AND self-verifies (same DoD rigor), with NO
independent Adversary and no claim/review handoff. The control for measuring
what the AI adversary costs (its tokens, ~half of a loop-pair run) and buys
(independent cold verification vs self-certification).

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

examples/builder-solo/agents.toml

@@ -0,0 +1,68 @@
+# examples/builder-solo — a single Builder, NO Adversary (self-verification baseline).
+#
+# Same pattern + same task spec as ../builder-adversary, but there is only ONE agent: the Builder
+# builds AND verifies its own work, then self-certifies "## DONE". This is the control for measuring
+# what the independent AI Adversary actually costs (its tokens) and buys (independent cold
+# verification). No claim/review handoff — nothing to hand off to.
+#
+#   python3 ../../agents.py status --config agents.toml
+#   python3 ../../agents.py up     --config agents.toml      # needs `claude` on PATH
+
+[watchdog]
+signal_interval      = 30
+heavy_interval       = 300
+limit_probe_fallback = 300
+limit_reset_slack    = 45
+stall_grace          = 180
+
+[defaults]
+session_prefix = "solo-"
+log_dir        = ".ao-state"
+backend        = "claude"        # set to "demo" for a dependency-free mechanics-only run
+model          = "claude-sonnet-4-6"
+watch          = "heal"
+
+[backend.claude]
+bin             = "claude"
+flags           = "--dangerously-skip-permissions"
+remote_control  = true
+supports_resume = true
+prompt_delivery = "arg"
+process_name    = "claude"
+submit_key      = "Enter"
+stall_idle      = 300
+active_re = "esc to interrupt|Running tool|⠇|⠙|· \\d+"
+limit_re  = "spend limit|usage limit|limit reached|reached your .*limit|out of (credits|tokens)"
+fatal_re  = "redacted_thinking|blocks cannot be modified|cannot be modified"
+
+[backend.demo]
+bin             = "echo '[demo] {session} up (kickoff: {kickoff})'; exec sleep 1000000"
+prompt_delivery = "exec"
+
+# The lone builder — builds and self-verifies.
+[[agent]]
+name  = "builder"                # tmux session: solo-builder
+kind  = "loop"
+role  = "builder"                # kickoff = prompts/kickoff.md (per phase) + prompts/builder.md
+dir   = "./work"
+watch = "heal+stall"
+
+[[service]]
+name    = "cleanlogs"
+command = "python3 ../../agent-log.py follow-all"
+dir     = "."
+
+# Phase machine. No handoff (single agent); the watchdog auto-advances when the builder writes
+# "## DONE" to the phase status file (read from handoff.repo's state_subdir).
+[loop]
+state_file       = "phase-idx"
+resume_phase     = true
+auto_advance     = true
+done_marker      = "## DONE"
+kickoff_template = "prompts/kickoff.md"
+roles_dir        = "prompts"
+handoff = { repo = "./work", state_subdir = "machine-docs" }
+phases = [
+  { id = "wc",   plan = "plans/wc.md",   status = "STATUS-wc.md" },
+  { id = "json", plan = "plans/json.md", status = "STATUS-json.md" },
+]