Delegate recovery middleware to toolhive-core with observability hooks

[JAORMX]

Summary

Wave 1 of the toolhive→toolhive-core migration: pkg/recovery becomes a thin shim over toolhive-core/recovery (v0.0.36, stacklok/toolhive-core#203), keeping ToolHive's observability wiring:

• Core's WithPanicHandler hook is wired to a local panicHandler:
  • RecordError → OTel span RecordError + error status (sanitized message, no panic value in telemetry)
  • ReportPanic → sentry.RecoverPanic (raw value, so panics still appear as Sentry Issues)
• ErrAbortHandler re-panic semantics now live in core; the existing TestRecoveryMiddleware_RePanicsErrAbortHandler exercises them through the shim unchanged.
• Factory pattern (MiddlewareType, FactoryMiddleware, CreateMiddleware) and the Middleware signature are unchanged — callers (pkg/api/server.go, pkg/runner/*, pkg/vmcp/server) untouched.

Net −28 LOC. Bumps toolhive-core to v0.0.36.

Test plan

• task build, task lint-fix — clean
• go test ./pkg/recovery/... ./pkg/runner/... ./pkg/api/... ./pkg/vmcp/server/... — all pass

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.56%. Comparing base (3d44435) to head (b33e274).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6145      +/-   ##
==========================================
- Coverage   72.63%   72.56%   -0.08%     
==========================================
  Files         736      736              
  Lines       76355    76340      -15     
==========================================
- Hits        55463    55398      -65     
- Misses      16955    17019      +64     
+ Partials     3937     3923      -14     

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