gate the raw-HTML default instead of remembering it

Since Arc 1 the latent list has carried "raw HTML is omitted only because
goldmark's default omits it". Shortcodes were the trigger, and they came and went
without needing unsafe mode — a call renders a theme template (ADR-0036). So the
right close is not a note saying we got away with it, but a gate: verify.sh now
fails on WithUnsafe in any non-comment line under cmd/ or internal/.

Proved both directions before keeping it. The first version also failed on the
comment in render.go that explains the rule — a gate that fires on its own
documentation is one nobody keeps, so it now skips comment lines. That is the
seventh gate defect found by running against real code rather than reasoning
about it.

The latent row is gone rather than reworded, and the untrusted-boundary row says
which half is now mechanism and which half still isn't.

docs/state.md

@@ -61,10 +61,9 @@ with a stated reason. A list nothing drains is a graveyard of known defects.
 | Item | Why it waits | Trigger to fix |
 |---|---|---|
 | No mechanical check that the counters are *correct* | Accepted at the Arc 1 boundary: the coupling gate makes forgetting them impossible, which is the real failure mode, and checking the values needs code to count | The first page-level transform (queue 15), now that the transform counter means something narrower |
-| No mechanical gate on the untrusted boundary (ADR-0003) | Scheduled to Arc 3: nothing untrusted is read yet | The comment path — a test that untrusted input reaches no shortcode or template evaluation |
+| No mechanical gate on the untrusted boundary (ADR-0003) | Scheduled to Arc 3: nothing untrusted is read yet. Half of it is now mechanical — `verify.sh` rejects `WithUnsafe`, so authored Markdown cannot become HTML — but there is still no check that a *future* untrusted source stays out of shortcode and template evaluation | The comment path — a test that untrusted input reaches no shortcode or template evaluation |
 | `date` stays in `Extra` after being lifted onto `Bundle.Date`, unlike `title`, `aliases`, `tags` and `order`, which are deleted | Spotted while adding `order`; the theme contract says `Extra` holds what the parser does not name, so one of the two is wrong. Harmless today — a template reading `.Extra.date` gets the raw YAML value | Whatever next reads `Extra` generically: feeds (queue 14) or `check` (17) |
 | Sequence resolution rescans the index on every bundle request — two passes over every key, each doing a `Lookup` | No cache exists anywhere yet, and a site of this size resolves in microseconds. Measuring first is the rule (queue 16) | The page cache (queue 16), which is the thing that makes the cost visible |
-| Raw HTML in Markdown is omitted only because goldmark's default omits it | Shortcodes landed without unsafe mode — a call renders through a template instead (ADR-0036), so the feared trigger came and went. What remains is that nothing *stops* a later change from enabling `html.WithUnsafe()`, which would silently turn authored Markdown into an injection path | Now: a gate rejecting `WithUnsafe` anywhere in the tree, so the rule is mechanism rather than memory |
 
 ## Open questions