docs: examples review — 2026 relevance audit + disposition recommendations

New docs/plans/2026-07-28-examples-review.md from a 10-agent audit of all
53 active examples (workflow wf_5bfe1540-030, head 418d631):

- Recommendations: 4 archive, 1 merge, 6 migrate-to-2026, 30 update,
  2 keep, 10 keep-2025-pinned. Recommendations only — nothing moves
  without maintainer sign-off.
- Headline: 14 examples are misleading on the 2026 default lane — they
  build green but teach session/GET-SSE/initialize-era idioms that fail
  or silently no-op against their own binary (worst: binaries printing
  broken curl commands from their own stdout).
- Itemized staleness evidence per example (.version("0.3.47") sweep,
  dead README links, phantom tools documented but not registered).
- Disposition dependencies (doc links, stateful-server re-pin,
  session-management-compliance-test manifest pin) + cross-checks
  (EXAMPLES.md, EXAMPLES_PIN stale capture date).
- New-examples section: 8 proposals (subscriptions/listen pair, MRTR
  elicitation round-trip, request-scoped observability, browser-facing
  Origin policy, OAuth scoped server, bilingual fleet client,
  x-mcp-header routing, completion provider) — each with why, learning
  value, spec match (driver-doc anchor), and human usefulness.

Author: hortovanyi