HS: cookie API (+3 tests, partial)

Three-part change: (a) tests/hs-run-filtered.js gets a per-test
__hsCookieStore Map, a globalThis.cookies Proxy, and a
document.cookie getter/setter that reads/writes the store. Per-test
reset clears the store. (b) generate-sx-tests.py declares cookies in
the test header and emits hand-rolled deftests for basic set / update
/ length-when-empty (the three tractable tests). (c) regenerated
spec/tests/test-hyperscript-behavioral.sx via mcp_hs_test.regen.

No .sx edits — `set cookies.foo to 'bar'` already compiles to
(dom-set-prop cookies "foo" "bar") which routes through host-set!.

Suite hs-upstream-expressions/cookies: 0/5 → 3/5.
Smoke 0-195 unchanged at 170/195.

Remaining `basic clear` (needs hs-method-call host-call dispatch) and
`iterate` (needs hs-for-each host-array recognition) need runtime.sx
edits — deferred to a future sx-tree worktree.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plans/hs-conformance-to-100.md

@@ -119,7 +119,7 @@ Orchestrator cherry-picks worktree commits onto `architecture` one at a time; re
 
 32. **[blocked: environment + scope. (env) The `loops/hs` worktree at `/root/rose-ash-loops/hs/` ships without a built sx-tree MCP binary; even after running `dune build bin/mcp_tree.exe` on this iteration, the tools don't surface to the current session — they'd need to load at session start, and rebuilding doesn't re-register them. CLAUDE.md mandates sx-tree for any `.sx` edit and a hook blocks Edit/Read/Write on `.sx`/`.sxc`. (scope) The cluster needs coordinated changes across `lib/hyperscript/parser.sx` (recognise `on mutation of <filter>` with attribute/childList/characterData/`@name [or @name]*`), `lib/hyperscript/compiler.sx` (analogue of intersection's `:having`-style attach call passing filter info), `lib/hyperscript/runtime.sx` (`hs-on-mutation-attach!` constructing real `MutationObserver` with config matched to filter, dispatching `mutation` event with detail), `tests/hs-run-filtered.js` (replace the no-op MutationObserver mock with a working version + hook `El.setAttribute`/`appendChild`/etc. to fire registered observers), `tests/playwright/generate-sx-tests.py` (drop 7 mutation entries from `SKIP_TEST_NAMES`). The current parser drops bodies after `of` because `parse-on-feat` only consumes `having` clauses — confirmed via compile snapshot (`on mutation of attributes put "Mutated" into me` → `(hs-on me "mutation" (fn (event) nil))`). Recommended path: dedicated worktree with sx-tree loaded at session start, multi-commit (parser, compiler+attach, mock+runner, generator skip-list pruning).] MutationObserver mock + `on mutation` dispatch** — 15 tests in `on`. Add MO mock to runner. Compile `on mutation [of attribute/childList/attribute-specific]`. Expected: +10-15.
 
-33. **[pending] cookie API** — 5 tests in `expressions/cookies`. `document.cookie` mock in runner + `the cookies` + `set the xxx cookie` keywords. Expected: +5.
+33. **[done (+3) — partial, `basic clear cookie values work` needs `hs-method-call` runtime fallback to dispatch unknown methods through `host-call` (current `hs-method-call` returns nil for non-{map,push,filter,join,indexOf} methods, so `cookies.clear('foo')` is silently a no-op); `iterate cookies values work` needs `hs-for-each` to recognise host-array/proxy collections (currently `(list? collection)` returns false for the JS Proxy so the loop body never runs). Both need runtime.sx edits → next worktree.] cookie API** — 5 tests in `expressions/cookies`. `document.cookie` mock in runner + `the cookies` + `set the xxx cookie` keywords. Expected: +5.
 
 34. **[pending] event modifier DSL** — 8 tests in `on`. `elsewhere`, `every`, `first click`, count filters (`once / twice / 3 times`, ranges), `from elsewhere`. Expected: +6-8.
 
@@ -177,6 +177,9 @@ Many tests are `SKIP (untranslated)` because `tests/playwright/generate-sx-tests
 
 (Reverse chronological — newest at top.)
 
+### 2026-04-25 — cluster 33 cookie API (partial +3)
+- No `.sx` edits needed — `set cookies.foo to 'bar'` already compiles to `(dom-set-prop cookies "foo" "bar")` which becomes `(host-set! cookies "foo" "bar")` once the `dom` module is loaded, and `cookies.foo` becomes `(host-get cookies "foo")`. So a JS-only Proxy + Python generator change does the trick. Two parts: (a) `tests/hs-run-filtered.js` adds a per-test `__hsCookieStore` Map, a `globalThis.cookies` Proxy with `length`/`clear`/named-key get traps and a set trap that writes the store, and a `Object.defineProperty(document, 'cookie', …)` getter/setter that reads and writes the same store (so the upstream `length is 0` test's pre-clear loop over `document.cookie` works). Per-test reset clears the store. (b) `tests/playwright/generate-sx-tests.py` declares `(define cookies (host-global "cookies"))` in the test header and emits hand-rolled deftests for the three tractable tests (`basic set`, `update`, `length is 0`). Suite hs-upstream-expressions/cookies: 0/5 → 3/5. Smoke 0-195 unchanged at 170/195. Remaining `basic clear` and `iterate` tests need runtime.sx edits (hs-method-call fallback + hs-for-each host-array recognition) — out of scope for a JS-only iteration.
+
 ### 2026-04-25 — cluster 32 MutationObserver mock + on mutation dispatch (blocked)
 - Two issues conspire: (1) `loops/hs` worktree has no pre-built sx-tree binary so MCP tools aren't loaded, and the block-sx-edit hook prevents raw `Edit`/`Read`/`Write` on `.sx` files. Built `hosts/ocaml/_build/default/bin/mcp_tree.exe` via `dune build` this iteration but tools don't surface mid-session. (2) Cluster scope is genuinely big: parser must learn `on mutation of <filter>` (currently drops body after `of` — verified via compile dump: `on mutation of attributes put "Mutated" into me` → `(hs-on me "mutation" (fn (event) nil))`), compiler needs `:of-filter` plumbing similar to intersection's `:having`, runtime needs `hs-on-mutation-attach!`, JS runner mock needs a real MutationObserver (currently no-op `class{observe(){}disconnect(){}}` at hs-run-filtered.js:348) plus `setAttribute`/`appendChild` instrumentation, and 7 entries removed from `SKIP_TEST_NAMES`. Recommended next step: dedicated worktree where sx-tree loads at session start, multi-commit shape (parser → compiler+attach → mock+runner → generator skip-list).