fix: address Copilot review round 1 on #2251

- skills.ts: report a manifest that omits the skill's own SKILL.md
  (an empty list included), duplicate URIs, entries outside the skill
  root, and a missing size. `Conforms` was reachable for manifests that
  break invariants SEP-2640 states.
- skills.ts: cross-check the declared byte length before hashing. A size
  that disagrees fails verification on its own — the digest is taken over
  the bytes the server served, so agreeing with it says nothing about
  whether the manifest describes them.
- skills.ts: copy the view instead of slicing its backing store in
  `sha256Digest`. `SharedArrayBuffer.prototype.slice()` returns another
  SharedArrayBuffer, which `crypto.subtle.digest` rejects — the cast
  claimed to handle the exact input that would have thrown. No cast now.
- skills.ts: state the one obligation NOT checked here — that an entry's
  frontmatter matches the fetched SKILL.md's. The digest cannot cover it,
  and closing it needs a YAML parser, so it is tracked on #2248.
- managedSkillsState: cap the walk at LIST_MAX_PAGES. The repeated-cursor
  guard only catches a server stuck on one cursor; endlessly unique ones
  walked forever. Raises rather than truncating, like the salvage walk.
- managedSkillsState: gate every write on a session generation, so a walk
  that resolves after a disconnect or destroy cannot repopulate a cleared
  store or deliver the previous session's skills into the next.
- inspectorClient: send a cursor when it is `!== undefined`, not when it
  is truthy. An opaque cursor may be `""`, and dropping it re-requested
  page one — which the store then reported as a repeated-cursor failure.
- SkillsScreen: key verdict invalidation on the manifest (URI + digests +
  sizes), not the URI alone. A Refresh that changed the manifest left a
  green badge attached to a digest nothing had checked.
- SkillsScreen: epoch-guard every read continuation, so a fetch that
  resolves after the selection moved on cannot write into the new one.
- SkillsScreen: bound "Verify all" to 4 concurrent reads. A conforming
  manifest may hold 512 files.
- skillsSchemas: drop the guessed `resources/directory/read` result
  schema. Nothing calls it, so an unverified shape could sit wrong
  indefinitely; phase 3 adds it against the normative text.
- skills-http.json: declare the extension bare. It advertised
  `directoryRead: true` with no handler, so Connection Info reported
  "Supported" for a method that answers -32601.
- types.ts: restore the Tasks doc comment the Skills interface displaced.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018kfrH3uRNUM4JAk1reKtyY
Signed-off-by: cliffhall <cliff@futurescale.com>

test-servers/configs/skills-http.json

@@ -5,9 +5,7 @@
   },
   "tools": [{ "preset": "echo" }],
   "resources": [],
-  "skills": {
-    "directoryRead": true
-  },
+  "skills": {},
   "transport": {
     "type": "streamable-http",
     "port": 3230

test-servers/src/composable-test-server.ts

@@ -831,10 +831,11 @@ export function createMcpServer(config: ServerConfig): McpServer {
     };
   }
 
-  // Skills extension (SEP-2640): a server-declared extension, advertised with
-  // its one sub-option. `directoryRead` is opt-in per config so a client can be
-  // exercised against both a server that offers `resources/directory/read` and
-  // one that does not.
+  // Skills extension (SEP-2640): a server-declared extension. `directoryRead`
+  // is opt-in per config and stays OFF in `skills-http.json` until the fixture
+  // actually serves `resources/directory/read` — advertising a sub-option this
+  // server would answer `-32601` for would make Connection Info report
+  // "Supported" for a method that is not (phase 3, #2248).
   if (config.skills) {
     capabilities.extensions = {
       ...(capabilities.extensions ?? {}),