v0.2.0 — first non-alpha release

First tagged release without a pre-release suffix: the public API
surface described in docs/getting-started/api-reference.md is now
considered stable enough for production pilots, and breaking changes
from here on bump the minor version per SemVer 0.x rules.

Added

• enduser.id on exception records: the structured exception record
  now carries the authenticated user's id (guests omit it), so issue
  tooling can count affected users per error group, Sentry-style.

Fixed

• Unbounded recursion in FailSafe during report(): the default
  failure handler is report(), and the exception subscriber runs inside
  report() — so a guarded path that kept failing while an exception was
  being reported (e.g. the enduser.id auth lookup with the database down)
  re-entered the subscriber on every cycle and recursed until memory
  exhaustion. FailSafe::handle() now carries a re-entrancy latch: a
  telemetry failure that occurs while another telemetry failure is already
  being reported is swallowed instead of re-reported.