refactor(wiki): migrate this repo's .wiki/ to canonical Karpathy layout

Stop being inconsistent with our own fixed project-bootstrap template.

- SUMMARY.md → index.md (catalog by type, with one-line hooks)
- source/*.md → concepts/*.md (with `git mv` so history is preserved)
- WORKFLOW.md removed (workflow lives in wiki-maintainer, not duplicated here)
- New: .wiki/CLAUDE.md (project schema, Karpathy gist URL pinned at top)
- New: log.md (append-only op log; backfilled with prior decisions)
- New: overview.md (single project intro page)
- New: raw/README.md (immutability note; replaces .gitkeep placeholder)
- Empty .gitkeep added to entities/, packages/, sources/
- Migrated pages got `type: concept` frontmatter

After this, wiki-maintainer reads .wiki/CLAUDE.md → index.md as it expects,
and the layout matches what newly-bootstrapped projects will look like.

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

.wiki/concepts/wiki-realignment.md

@@ -0,0 +1,56 @@
+---
+title: Wiki realignment to Karpathy canon
+type: concept
+updated: 2026-04-28
+---
+
+# Wiki realignment to Karpathy canon
+
+_2026-04-28._
+
+## What was wrong
+
+`project-bootstrap` Step 3 was creating `.wiki/SUMMARY.md`, `WORKFLOW.md`,
+and a `source/` folder. **None of these match** Karpathy's LLM Wiki pattern
+or what the `wiki-maintainer` skill reads:
+
+| Bootstrap created | Canon expects |
+|---|---|
+| `SUMMARY.md` | `index.md` |
+| `WORKFLOW.md` (duplicates skill) | (no such file — workflow lives in `wiki-maintainer`) |
+| `source/` (singular) | `sources/` (plural) |
+| (missing) | `.wiki/CLAUDE.md` schema |
+| (missing) | `log.md` (append-only op log) |
+| (missing) | `entities/`, `concepts/`, `packages/`, `overview.md` |
+| (missing) | `raw/README.md` |
+
+When `wiki-maintainer` triggered, it had to bend around an invented layout:
+the schema file it expects to read first wasn't there at all, and the
+catalog had the wrong name.
+
+## Fix
+
+Rewrote `project-bootstrap` Step 3 to create the canonical layout verbatim:
+
+```
+.wiki/
+  CLAUDE.md          schema (project-specific conventions)
+  index.md           catalog of all pages
+  log.md             append-only op log: ## [YYYY-MM-DD] op | desc
+  overview.md        single human-readable project overview
+  raw/README.md      raw/ is immutable; this documents that
+  entities/ concepts/ packages/ sources/   (with .gitkeep)
+```
+
+Each file has its initial content baked into the SKILL.md so bootstrap can
+write them without external assets.
+
+The Karpathy gist is pinned at the top of `.wiki/CLAUDE.md`:
+**https://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f**
+
+## What about this repo's `.wiki/`?
+
+This repo was itself bootstrapped with the old buggy layout. Its `.wiki/`
+still uses `SUMMARY.md` + `source/`. Migrating to canon is a directory
+rename + file moves; queued as a backlog task to do consciously rather than
+silently bundling it here.