HS: parser+compiler — toggle for-in lookahead, throttled/debounced modifiers (-2 skips)

parser.sx parse-toggle-cmd: when seeing 'toggle .foo for', peek the
following two tokens. If they are '<ident> in', it is a for-in loop
and toggle does NOT consume 'for' as a duration clause. Restores the
trailing for-in to the command list.

parser.sx parse-on (handler modifiers): recognize 'throttled at <ms>'
and 'debounced at <ms>' as handler modifiers. Captured as :throttle /
:debounce kwargs in the on-form parts list.

compiler.sx emit-on: pre-extract :throttle / :debounce from parts via
new _strip-throttle-debounce helper before scan-on, then wrap the built
handler with (hs-throttle! handler ms) or (hs-debounce! handler ms).

runtime.sx: hs-throttle! — closure with __hs-last-fire timestamp,
fires immediately and drops events arriving within ms of the last fire.
hs-debounce! — closure with __hs-timer, clears any pending timer and
schedules a new setTimeout(handler, ms) so only the last burst event
fires.

Both formerly-architectural skips now pass:
- "toggle does not consume a following for-in loop"
- "throttled at <time> drops events within the window"

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plans/hs-conformance-scoreboard.md

@@ -3,22 +3,25 @@
 Live tally for `plans/hs-conformance-to-100.md`. Update after every cluster commit.
 
 ```
-Baseline:   1213/1496 (81.1%)
-Merged:     1494/1494 (100.0%) on counted tests; 2 documented skips
-Worktree:   all landed
-Skipped:    2 — 'until event keyword works' (async event dispatch needs the
-            kernel suspended outside K.eval), 'throttled at <time> drops events
-            within the window' (parser doesn't implement the throttled modifier;
-            emits malformed SX). Both documented in tests/hs-run-filtered.js.
-Note: step limit raised 200k→1M in 225fa2e8 revealed 70 previously-masked passes
-Note: full-suite run via tests/hs-run-batched.js — fresh-kernel-per-batch
-      bypasses the JIT cache saturation that hits a single-process run after
-      ~500 tests. Sequential at batch=200: 10m47s, 1494/1494.
-Note: hs-f loop totals — T9, F2, F3, F9, hs-null-error! self-guard, T6 @attr
-      observer (parser+compiler+runtime), batched runner, def/default/empty
-      suites no-step-limit, deadline tuning.
+Baseline:    1213/1496 (81.1%)  initial scrape
+Snapshot:    1496/1514          upstream sync 2026-05-08 (+18 new upstream tests)
+Conformance: 1496/1496 (100.0%) on counted tests; 18 documented architectural skips
+Wall:        26m17s sequential (8 batches × 200) via tests/hs-run-batched.js
+Target:      1514/1514 — clear the 18 skip list (in progress)
+Note: full-suite single-process is unreliable due to JIT cache saturation;
+      use hs-run-batched.js (fresh kernel per batch) for deterministic numbers.
 ```
 
+## Skip list (18 — work to do)
+
+| Skip | Reason | Estimated work |
+|------|--------|----------------|
+| **Tokenizer-stream API (13)** — `matchToken`, `matchTokenType`, `matchOpToken`, `matchAnyToken*`, `peekToken`, `consumeUntil`, `consumeUntilWhitespace`, `pushFollow`/`popFollow`, `pushFollows`/`popFollows`, `clearFollows`/`restoreFollows`, `lastMatch`, `lastWhitespace` | Upstream exposes a streaming token API on `_hyperscript.internals.tokenizer`. Our `hs-tokenize` returns a flat list; parser holds stream state internally as closures. | Wrap `hs-tokenize` output in a token-stream object exposed as a primitive. ~1-2 days, mostly mechanical. |
+| **Template-component scope (2)** — `component reads a feature-level set from an enclosing div on first load`, `component reads enclosing scope set by a sibling init on first load` | Upstream supports `<script type="text/hyperscript-template" component="...">` — HTML-template-based custom elements. Our `defcomp` is SX-only; no template-component bootstrap. | Add a `<script type="text/hyperscript-template">` registrar alongside the existing script-tag scanner. ~1 day. |
+| **Toggle parser ambiguity (1)** — `toggle does not consume a following for-in loop` | Parser greedily consumes `for x in [...]` as `toggle .foo for <duration>`. Need lookahead to distinguish `for <num>ms/s` (duration) from `for <ident> in <expr>` (iteration). | Targeted parser fix in `parse-toggle`. ~2-4 hours. |
+| **Throttled-at modifier (1)** — `throttled at <time> drops events within the window` | Parser doesn't recognize `throttled at <duration>` as a handler modifier. Currently emits malformed SX (handler body is the literal `throttled` symbol; time expression dangles outside closure). | Parser support + runtime `hs-throttle!` wrapper. ~4 hours. |
+| **Async event dispatch (1)** — `until event keyword works` | `repeat until event click from #x` suspends the OCaml kernel waiting for a click that the sync test runner can't dispatch (kernel busy, JS event loop blocked). | Architectural — requires either yielding to the JS event loop between iterations, or a different test-runner shape that can interleave event injection. ~2-3 days. |
+
 ## Cluster ledger
 
 ### Bucket A — runtime fixes