feat: scaffold redsen-lean-harness v0.1.0

Recovered from crashed session (Node OOM). Repo contains full P0-P6
scaffold: plugin.json/marketplace.json, AGENTS.md, ADRs 0001-0006,
lh CLI (init/index/graph/lane/run/memory/host/report/doctor), 10
.github/agents, 12 CLI skills, instructions, context7 mcp.json, and
unit/e2e test suite.

Fixed: run.mjs read --in-tokens/--out-tokens but tests and CLI docs
use --input-tokens/--output-tokens, so telemetry totals were always 0.
Now accepts both forms.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docs/adr/0002-web-tree-sitter-index.md

@@ -0,0 +1,45 @@
+# ADR 0002 — web-tree-sitter (WASM) for the code index, with a regex fallback
+
+- **Status**: Accepted
+- **Date**: 2026-09-09
+
+## Context
+
+The harness must work on brownfield repos in *any* language, be OS-agnostic, and install with
+no build step. It needs a token-budgeted repo map so agents stop reading whole files.
+
+Candidates evaluated:
+
+| Option | Verdict |
+| --- | --- |
+| `tree-sitter` (native bindings) | Requires a native compile toolchain — fails "easy install" |
+| **`web-tree-sitter` (WASM)** | Pure npm, no compiler, runs anywhere Node runs |
+| `universal-ctags` | External binary the user must install; 200+ languages but not npm-installable |
+| `ast-grep` | Prebuilt binary via npm, good, but heavier and rule-oriented rather than map-oriented |
+| SCIP / LSIF | Per-language indexers — far too much install surface |
+| Zoekt | Requires Docker |
+| Host `/lsp` | Excellent fidelity but CLI-only and not available in every host/language |
+
+## Decision
+
+Use **`web-tree-sitter`**, the sole runtime dependency.
+
+Grammars are **not vendored** and **not fetched at import time**. They are cached lazily under
+`.agents/.cache/wasm/` and only downloaded when the user passes `--fetch`. When a grammar is
+absent, the indexer **silently degrades to a per-language regex extractor** and reports the
+degradation in `lh index --stats`.
+
+The repo map is ranked with a hand-rolled PageRank over the reference graph and truncated to
+`config.index.budget` tokens, degrading full signatures → names → file-level counts.
+
+## Consequences
+
+- `lh index` works **fully offline** on first run, at lower fidelity. This is a hard requirement.
+- No compiler, no Docker, no external binary, no service. `npm install` is the whole setup.
+- Fidelity varies by language and by whether a grammar has been fetched. `--stats` makes this visible.
+- We own a small glob matcher and a small PageRank implementation rather than taking dependencies.
+
+## Alternatives considered
+
+Rejected `--fetch`-by-default: it would make the first run fail on an air-gapped machine and
+would surprise users with network traffic. Opt-in is the safer default.