docs: THEORY-FEED direction doc (D127, D204–D206) (#211)

Adds `docs/THEORY-FEED.adoc`, the direction doc for **D127**. Under
D127, the theory, type, prover and language repos are feeders of
valence-shell, and their progress is judged by what they contribute
here.

## What the doc contains

- **A per-feeder map** for each of the 17 feeders: what it proves today,
what it feeds valence-shell, and its next direction.
- **A summary matrix** grading each link as M (mechanised), D (doc), C
(comment) or T (tooling).
- **Prioritised next work, NW-1 to NW-10.**

## Headline finding

No valence-shell proof file imports any feeder module today. Every link
is a comment, a doc or tooling.

## Rulings recorded in the doc

- **D204:** NW-1 is Arm A. absolute-zero factors out an abstract CNO
interface, and valence-shell instantiates it.
- **D205:** zerostep is dropped from the feeder set.
- **D206:** `feeds:valence-shell` is a repo-local label. It exists in
all feeders and is applied to 90 issues.

Standing umbrella: #210. The doc is docs-only and licensed CC-BY-SA-4.0.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_01SJGZgoR9ArMgxKcqG7ChW8

---------

Signed-off-by: Jonathan D.A. Jewell <6759885+hyperpolymath@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: 3 people

CLAUDE.md

@@ -139,7 +139,7 @@ deep-audit session). The corresponding Phase 4C design docs under
 - **4 doctest fixes**: Missing imports, PATH-dependent assertions
 - **Append redirection truncation**: `>>` used `File::create()` (truncates!) instead of `OpenOptions::append()` in `external.rs`
 - **`2>` tokenization**: `file2>out` incorrectly split as `file [2>] out` instead of `file2 [>] out` — now only treats `2>` as error redirect when `2` starts a new token
-- **Logical operator precedence**: `a && b || c` parsed as `a && (b || c)` — fixed to left-to-right `(a && b) || c` via `rposition`
+- **Logical operator precedence**: mixed AND/OR lists incorrectly grouped the OR expression first — fixed to left-to-right evaluation via `rposition`
 - **Shift overflow panic**: `$((1 << 64))` panicked — now returns error for shift counts >= 64
 - **Path traversal**: `resolve_path("../../etc/passwd")` could escape sandbox — now normalizes `..` components and clamps to root
 - **Version mismatch**: `main.rs` reported version 1.0.0 and "256 proofs" — fixed to 0.9.0 and "200+ theorems"