refactor(mcp): simplify tool bridge and remove AIContextToolPolicy

[jrepp]

Summary

• Restacked PR refactor(mcp): simplify tool bridge and remove AIContextToolPolicy #286 on top of PR feat(debugger): add statement stepping and polish script editor #292 (feat/script-debugger) so the advertised script-debugger MCP tools depend on the live recorder/debug-server implementation.
• Keeps PR refactor(mcp): simplify tool bridge and remove AIContextToolPolicy #286 scope to the MCP bridge/document-backend changes: advertise the script-debugger control tools through HypeMCPToolBridge, and make HypeMCPDocumentBackend fail closed for process-local debugger state.

Review Notes

• PR feat(debugger): add statement stepping and polish script editor #292 now supplies the underlying live debug-server handlers for hype_get_script_debugger_state, hype_set_script_tracing, hype_clear_script_trace, and hype_open_script_trace_source.
• With this stacking, debug/listTools from PR refactor(mcp): simplify tool bridge and remove AIContextToolPolicy #286 advertises tools that debug/callTool can route in the live app once PR feat(debugger): add statement stepping and polish script editor #292 is in the base.
• The document backend behavior remains intentionally fail-closed because static document backends do not own live trace state.
• No persistence, stack-document shape, network, keychain, or AI-context policy expansion found in the MCP diff.

Testing

• On PR refactor(mcp): simplify tool bridge and remove AIContextToolPolicy #286 stacked over PR feat(debugger): add statement stepping and polish script editor #292: scripts/test.sh --filter HypeMCPTests --filter HypeDebugServerScriptDebuggerToolTests passed: 18 tests.
• On PR feat(debugger): add statement stepping and polish script editor #292 directly: scripts/test.sh --filter HypeDebugServerScriptDebuggerToolTests --filter HypeTalkScriptTraceRecorderTests --filter HypeTraceConfigurationTests passed: 9 tests.
• On PR feat(debugger): add statement stepping and polish script editor #292 directly: scripts/test.sh --filter HypeMCPTests --filter HypeDebugServerScriptDebuggerToolTests --filter HypeTalkScriptTraceRecorderTests --filter HypeTraceConfigurationTests passed: 23 tests.