Addresses Copilot's review on #2035. All three findings reproduced against
the pinned SDK before acting.
1. `#` was misclassified as required. Measured: `x://a{#frag}` with no
`frag` expands to exactly `x://a`, a well-formed URI naming a real
resource -- unlike `{+path}` (`x://a/`) or a simple `{userId}`
(`file:///users//profile`), which leave an empty path segment. Moved `#`
into the omittable set; the required cases now assert what the URI
*becomes* when blank, so the rule is checked rather than asserted.
2. Delegating to the SDK did not actually give RFC 6570 expansion.
`UriTemplate.expandPart` takes an early `names.length > 1` branch that
raw-joins values, skipping both `encodeValue` and the operator prefix:
`x://{a,b}` with `a = "foo/bar"` expands to `x://foo/bar,q` -- the very
unencoded-slash defect this PR is about -- and `x://a{/p,q}` to
`x://ax y,z`. Only `?`/`&` are correct, being dispatched earlier.
Fixing that in the web client alone would have left the TUI and CLI
wrong, since `readResourceFromTemplate` expands through the same class.
So parse/classify/expand now live in `core/mcp/uriTemplate.ts` and both
call sites use it. The correction is surgical: a multi-name non-query
expression is expanded here and spliced in as literal text before the
SDK sees the template (safe -- both encoders escape `{`/`}`), while
every single-name and query expression still goes through the SDK
untouched. The preview applies the same correction, so it cannot
promise a URI that submitting would not send.
3. The showcase promised a blank `{?topic}` read that did not work.
`UriTemplate.match()` compiles `{?topic}` to a *required*
`\?topic=([^&]+)`, so `match("foobar://events")` returns null and the
read 404s. A real server exposes the unfiltered collection as its own
resource; the showcase now registers `foobar://events` so the
documented step resolves. Verified end to end through the CLI.
Signed-off-by: cliffhall <cliff@futurescale.com>