scaffold steer_heal: spec, repo infra, vendored deps

Setup per setup-repo conventions: uv + justfile + fast-dev-run on
wassname/qwen3-5lyr-tiny-random, package under src/steer_heal (config +
pipeline skeleton). Stages fail fast with NotImplementedError pointing at
the docs/vendor module to port from.

Design in spec.md: distil a steering-lite mean-diff teacher vector (iso-KL
dosed) into a conditioned LoRA, heal incoherency with a KL-rev-to-original
barrier, fold each round via w2schar gated bake, eval on tinymfv. Three
uncertainty gates (filter / heal / iterate) each with a UAT artifact.

Base model google/gemma-3-1b-it (RTX 3090, 24GB). Reference repos vendored
under docs/vendor (gitignored): steering-lite, isokl, tinymfv, w2schar-mini.
The lighter three are editable path deps; w2schar (py3.13 + flash-attn) is
reference-only, we copy its adapter/bake/plot modules.

Co-Authored-By: Claudypoo <288921227+claudypoo@users.noreply.github.com>

justfile

@@ -0,0 +1,47 @@
+set shell := ["bash", "-cu"]
+
+BASE := "uv run python -m steer_heal.run"
+SEEDS_3 := "41 42 43"
+
+# List available recipes
+default:
+    @just --list
+
+# Clone the vendored reference repos (editable path deps live here).
+vendor:
+    #!/usr/bin/env bash
+    set -eux
+    mkdir -p docs/vendor && cd docs/vendor
+    for r in steering-lite isokl_steering_calibration tinymfv w2schar-mini; do
+        [ -d "$r" ] || git clone --depth 1 "https://github.com/wassname/$r"
+    done
+
+# fast-dev-run: ONE end-to-end run of the real pipeline on the tiny-random model.
+# Real LLM, real eval, real I/O; only knob is scale. NOT a unit test.
+fast-dev-run *ARGS:
+    BEARTYPE=1 {{ BASE }} --fast-dev-run {{ ARGS }}
+
+# Real run on gemma-3-1b-it (24GB / RTX 3090). Set flash-attn first if installed.
+run *ARGS:
+    STEER_ATTN_IMPL=eager {{ BASE }} {{ ARGS }}
+
+# Queue sweeps (comment out completed; `just results` to check).
+queue:
+    #!/usr/bin/env bash
+    set -x
+    just sweep-reg
+
+# H: kl_rev heals best (mode-seeking suppresses low-base-prob = incoherent tokens).
+sweep-reg:
+    #!/usr/bin/env bash
+    set -x
+    export WANDB_RUN_GROUP="sweep-reg-$(date +%Y%m%d-%H%M)"
+    for seed in {{ SEEDS_3 }}; do
+        for reg in nll kl_fwd kl_rev wd; do
+            echo "=== reg=$reg seed=$seed ==="
+            {{ BASE }} --reg=$reg --seed=$seed
+        done
+    done
+
+# flash-attn: install a prebuilt wheel (see `flash-attn-prebuilt` skill), then
+# run with STEER_ATTN_IMPL=flash_attention_2.