Add sync and async session WebMCP support

[NikhilShahi]

Summary

Changes

Validation

• ruff check
• pytest

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Note

Medium Risk
New session feature and HTTP client behavior (GET timeouts, richer errors); tool invocations can have side effects and are explicitly not retried on failure.

Overview
Adds WebMCP page tools to the Python SDK so agents can discover and run document-bound tools in browser sessions created with enable_web_mcp.

client.sessions.webmcp (sync and async) exposes list_tools, blocking invoke, async start / get_result / cancel, with per-call HTTP timeouts tuned for long polls and invocations. Session CreateSessionParams and launch state gain enable_web_mcp; new Pydantic and TypedDict types live under hyperbrowser.models and hyperbrowser.types.

Transport GET now accepts an optional timeout; API errors surface code and details on HyperbrowserError. README documents usage and semantics (no auto-retry on mutations, ephemeral handles). Version 1.11.0; tests cover wire contract, validation, and typechecking.

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