Add ToolActivatedEvent and ToolCancelEvent - #7

Implements webmachinelearning/webmcp#245, with the event timing from webmachinelearning/webmcp#371.

Rebased onto main (after #12). #9 is based on this branch and needs a rebase.

Changes

• Define ToolActivatedEvent and ToolCancelEvent (src/events.ts) and install them as globals alongside ModelContext.
• Add ontoolactivated and ontoolcancel to ModelContext, sharing the existing event handler code with ontoolchange.
• Dispatch toolactivated at the ModelContext of the document that owns the tool, right after the execute callback is invoked (webmcp#371). If the callback detaches that document, DOM's inner invoke skips the listeners, with no extra check.
• Dispatch toolcancel when a caller aborts a callback that has started and not settled.
• Bump webmcp-types to ^0.1.10, which declares the new interfaces.
• New real-browser tests:
  • constructors and Web IDL conversion;
  • handler semantics;
  • event order on cancellation (callback, toolactivated, rejection, signal abort, toolcancel);
  • no events for calls that never start or have already settled;
  • events fire in the frame that owns the tool;
  • no toolactivated after the callback detaches its document.

Revisions

• Draft: checked against eada13b (the pin on main). Lifecycle event timing follows f2f2ae2 (webmcp#371). The other draft changes since eada13b (#345, #347, #254) are not reviewed here.
• WPT: fe52996 (unchanged).
• Types: [email protected].

Results

• Browser tests: 253 passed (Playwright Chromium, Firefox, WebKit, plus native Chromium). pnpm test:package passed.

• WPT in Chrome Canary 159.0.8153.0: 70 files, 190 subtests, zero unexpected results.

  Subtest result	Count
  PASS	112
  Expected FAIL	37
  Expected TIMEOUT	25
  Expected NOTRUN	16

  Files: 44 OK, 25 expected timeouts, 1 expected error.

• Firefox WPT could not be validated locally:

  • Nightly 162.0a1 (20261110053316) cannot load the WPT runner page (netReset);
  • Firefox 159.0.1 hits harness crashes in 7 files, none of them lifecycle-event tests.

  Firefox and Safari results come from CI.

Newly passing:

• all 38 IDL checks (idlharness expectations deleted);
• all of tool-activated-event (expectations deleted);
• the ToolCancelEvent constructor and synthetic-event cases;
• imperative/executeTool-abort: "caller abort propagates…" and "already-aborted … synchronously rejects".

Expected failures

• imperative/executeTool-events:
  • The first case asserts isTrusted, which cannot be true for script-dispatched events.
  • The other two cases use /common/blank.html frames, which do not load the polyfill.
• Two cases abort synchronously after executeTool(): imperative/executeTool-abort, "promise remains rejected…" (TIMEOUT), and tool-cancel-event, "ontoolcancel is invoked…" (TIMEOUT). The polyfill rejects before dispatching to the callback (the existing "Timing" limitation), so the callback never starts and no toolcancel fires.

Excluded

Declarative forms and CSS states remain unimplemented. Crashtests and non-testharness files are outside the suite.

This is not full conformance.