docs(agent): vendor-neutral agent docs — AGENTS.md entry, agent/ SoT, .claude shims

The repo is maintained by agents from multiple vendors, so agent
instructions move out of vendor-specific locations into shared,
git-tracked markdown:

- AGENTS.md is the new entry point for any harness; CLAUDE.md becomes a
  symlink to it (Claude Code keeps working unchanged).
- Skill bodies relocate to agent/: VERIFICATION.md (the enforcement
  rules, ex .claude/skills/nomarchy), DELEGATION.md (capability tiers
  light/standard/frontier, scout/runner role contracts, token economy,
  parallel fan-out — consolidates the CLAUDE.md model table, LOOP.md's
  economy section, and skill §6.5 into one place; vendor model names
  survive only in the per-harness mapping table), THEME-DESIGN.md
  (ex .claude/skills/theme, which previously lacked frontmatter).
- .claude/ shrinks to a thin Claude Code adapter: settings, subagent
  defs, and skill shims that route into agent/.
- Maps updated: agent/README.md (instructions vs state vs adapters),
  docs/README.md, README.md layout tree.

Cleanup: stale old_distro .gitignore entry dropped (dir long gone);
local result*/__pycache__ artifacts removed; JOURNAL.md rotated (29
recent entries kept, 120 older moved to agent/JOURNAL-ARCHIVE.md,
rotation rule documented in the header).

Verification: V0 (docs/meta only) — nix flake check --no-build exit 0
with the tracked symlink; grep sweep confirms no vendor model names
outside DELEGATION.md's mapping table.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -83,10 +83,10 @@ Flat on purpose. Two module trees, one options file each, no hidden layers.
 │   ├── ROADMAP.md                 #   design/decision records + shipped log
 │   ├── HARDWARE.md                #   firmware, profiles, drivers
 │   ├── TESTING.md · RECOVERY.md · OVERRIDES.md · MIGRATION.md
-├── agent/                         # agent loop state — map: agent/README.md
-│                                  #   BACKLOG (executable queue), LOOP, GOALS, …
-├── CLAUDE.md                      # agent harness entry (points at agent/ + docs/)
-├── .claude/                       # Claude Code only: permissions + subagents
+├── agent/                         # agent instructions + loop state — map: agent/README.md
+│                                  #   BACKLOG (executable queue), LOOP, VERIFICATION, …
+├── AGENTS.md                      # agent entry, any vendor (CLAUDE.md symlinks here)
+├── .claude/                       # Claude Code adapter: permissions + subagent/skill shims
 └── tools/                         # maintainer-only
     ├── import-palettes.py         #   converts old-distro themes → JSON + assets
     ├── test-live-iso.sh           #   build the ISO + boot it in QEMU