fix: bound the resource file name, and move its typography into the theme (#2263)

Copilot review round 9, two findings.

The Skill Resource control shows the displayed file's name, and that control is
PINNED — it never scrolls — so a resource URI ending in a long breakable segment
grew the header. Fifth instance of the same class.

It took three attempts, and the mutation table is what exposed each one.
`lineClamp: 1` stopped the text wrapping but the row then wrapped the caption
onto its own line (+30.6px), because flexbox wraps before it shrinks. A
`nowrap` row improved that to +21.7px but Mantine's Accordion label wrapper
still would not let the caption shrink, so `miw: 0` had nothing to act on. A
hard `maw: "50%"` gives the ellipsis a definite width, and the control now grows
by 0px.

Worth recording that the FIRST version of that guard passed against the defect:
it asserted an absolute `height < 120px`, which an unclamped name satisfies
because it only wraps to a few lines. Comparing the control against its own
baseline — measured with a short name, then re-measured after selecting the
hostile one — is what makes it detect anything at all.

Second finding: `SkillDescription` carried `size: "sm"`, leaving typography at
the call site directly beneath a comment of mine asserting that these constants
carry layout only and that typography belongs in a `ThemeText` variant. Added a
`skillDescription` variant; only the clamp stays here.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R4441JdNLZerCVM7mDDSfB
Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/theme/Text.ts

@@ -61,6 +61,9 @@ export const ThemeText = Text.extend({
         root: { fontWeight: 600, fontSize: "var(--mantine-font-size-lg)" },
       };
     }
+    if (props.variant === "skillDescription") {
+      return { root: { fontSize: "var(--mantine-font-size-sm)" } };
+    }
     if (props.variant === "monoCaption") {
       return {
         root: {