chore: v1-prep hygiene sweep — LICENSE (MIT), fixtures under tools/, doc staleness

Three-way audit ahead of v1 (structure/necessity, docs-vs-code drift,
mechanical checkers) came back clean: zero dead files, zero doc hard
errors, all 92 options documented, all consistency checkers green, no
untracked files. What it did surface, fixed here:

- LICENSE was missing entirely — the one hard launch blocker. MIT
  (Bernardo's call), pointer at the README foot.
- checks/ was the only top-level dir outside the documented layout rule;
  its two state-legacy-name fixtures moved to tools/fixtures/ (Bernardo
  chose move over documenting an exception), flake.nix refs + drift
  messages updated.
- Doc staleness: two leftover "theme-state" leads (HARDWARE.md,
  REQUIREMENTS.md) now say state.json; VISION Theme C charge-limit row
  gets its ✓; VISION agent-slices datestamp bumped.
- The idle.nix miniTransition duplication (same binary name, lossy
  subset of the real display-transition tool) is deliberately NOT
  refactored here — filed as PROPOSED #150 with the audit evidence.

Wallpapers-in-repo (97 MB) is the known LATER artifact-split item, not
re-filed.

Verification: V0 — nix flake check --no-build green after the fixture
move (state-legacy-name's eval asserts exercise the new paths); doc
edits prose-reviewed. Audits by three Sonnet passes; triage on Fable.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

flake.nix

@@ -1558,8 +1558,8 @@
             let
               inherit (nixpkgs) lib;
               expect = cond: msg: lib.assertMsg cond "state-legacy-name: ${msg}";
-              legacy = ./checks/fixtures/legacy-state;
-              none = ./checks/fixtures/no-state;
+              legacy = ./tools/fixtures/legacy-state;
+              none = ./tools/fixtures/no-state;
               evalsOk = src:
                 (builtins.tryEval
                   (builtins.isAttrs (self.lib.mkFlake { inherit src; username = "fixture"; })))
@@ -1568,9 +1568,9 @@
                 # Fixture drift: if someone adds a state.json here the check
                 # would still pass, while testing nothing at all.
                 expect (builtins.pathExists (legacy + "/theme-state.json"))
-                  "fixture drift: checks/fixtures/legacy-state has no theme-state.json"
+                  "fixture drift: tools/fixtures/legacy-state has no theme-state.json"
                 && expect (! builtins.pathExists (legacy + "/state.json"))
-                  ("fixture drift: checks/fixtures/legacy-state also has a state.json, "
+                  ("fixture drift: tools/fixtures/legacy-state also has a state.json, "
                     + "so it no longer exercises the legacy-only path")
                 && expect (evalsOk legacy)
                   ("mkFlake cannot evaluate a checkout carrying only theme-state.json — "