qlora+bs=4 batched heal, walk-C bisection, round-loosened barrier

- QLoRA (4-bit NF4) base frees ~6GB -> train_bs=4 + grad_accum=4
  (block/Linear-level hooks survive bnb Linear4bit: add to dequantized
  output, same pattern as peft randlora/bnb.py)
- walk-C: log-kappa bisection dose controller, ~5 probes of 8 gens to
  highest kappa with >=75% filter survival, then collect to n_keep
- filter: char-level n-gram rep (catches TTTT/!!!! loops), ppl over the
  tail 25% of completion (steering collapses mid-completion)
- lam_round_pow<0 loosens the KL-to-base barrier with round
  (lam_eff=lam/sqrt(1+N)): only the cumulative-vs-fixed-anchor barrier
  self-inflates with round; per-increment spectral_lam + weight_decay
  stay flat
- alphas capped at 1.0, gen_pass_target 0.75

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

uv.lock

@@ -11,7 +11,7 @@ resolution-markers = [
 ]
 
 [options]
-exclude-newer = "2026-05-30T09:16:42.439409688Z"
+exclude-newer = "2026-06-04T01:47:06.189839469Z"
 exclude-newer-span = "P5D"
 
 [[package]]
@@ -215,6 +215,22 @@ wheels = [
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 ]
 
+[[package]]
+name = "bitsandbytes"
+version = "0.49.2"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "numpy" },
+    { name = "packaging" },
+    { name = "torch" },
+]
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/d8/7d/f1fe0992334b18cd8494f89aeec1dcc674635584fcd9f115784fea3a1d05/bitsandbytes-0.49.2-py3-none-macosx_14_0_arm64.whl", hash = "sha256:87be5975edeac5396d699ecbc39dfc47cf2c026daaf2d5852a94368611a6823f", size = 131940, upload-time = "2026-02-16T21:26:04.572Z" },
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+    { url = "https://files.pythonhosted.org/packages/b6/d4/501655842ad6771fb077f576d78cbedb5445d15b1c3c91343ed58ca46f0e/bitsandbytes-0.49.2-py3-none-win_amd64.whl", hash = "sha256:2e0ddd09cd778155388023cbe81f00afbb7c000c214caef3ce83386e7144df7d", size = 55372289, upload-time = "2026-02-16T21:26:16.267Z" },
+]
+
 [[package]]
 name = "catalogue"
 version = "2.0.10"
@@ -2454,6 +2470,7 @@ dependencies = [
     { name = "accelerate" },
     { name = "baukit" },
     { name = "beartype" },
+    { name = "bitsandbytes" },
     { name = "datasets" },
     { name = "einops" },
     { name = "iso-kl-figure" },
@@ -2480,6 +2497,7 @@ requires-dist = [
     { name = "accelerate" },
     { name = "baukit", git = "https://github.com/davidbau/baukit.git" },
     { name = "beartype" },
+    { name = "bitsandbytes", specifier = ">=0.49.2" },
     { name = "datasets" },
     { name = "einops" },
     { name = "iso-kl-figure", editable = "docs/vendor/isokl_steering_calibration" },