chore(plan): triage the blocked queue after the rule-14 sweep

Records what the sweep measured, and separates "blocked on work" from
"blocked on you".

#1962 stays blocked, but for a DIFFERENT reason than the one on file. Both
environmental facts moved: ping_group_range now reads "0 2147483647" (was
"1 0"), which is why the five PingTests pass and why #2194 could land a real
round trip -- but socket(AF_INET, SOCK_RAW, IPPROTO_ICMP) returns EPERM here
(uid 1000, no CAP_NET_RAW). So the raw-socket fallback this ticket exists to
add cannot be exercised at all, and a second receive path with its own header
parsing and cross-process identifier matching must not ship unverified. The
gate is now CAP_NET_RAW, not ping_group_range.

Five tickets move blocked -> needs_user, each with the question recorded,
because their only remaining gate is a user decision:

  #1899 - the design PROVES its original requirement impossible (an owning
          handle to an object no shared_ptr owns cannot be manufactured, and
          enable_shared_from_this throws bad_weak_ptr on the 51
          automatic-storage declarations in this repository's own tests), so
          the user must choose the alternative.
  #2155 - premise re-verified against /rv: .NET does pass the timer as sender
          (Timer.cs:313), and it derives from Component, not Object -- but
          this port has NO Component class, so the obvious alternative does
          not exist. The design stands; SA-3 excludes vtable/base changes.
  #2058 - needs a new public constructor and new public members; SA-3 covers
          private members only and SA-8 is the opposite direction. Contrast
          #2150, which this sweep landed because the repository's own design
          record already classified it as additive.
  #2118 - /rv CONFIRMS the contract, but nlohmann retains no source spans, so
          honouring it is an architecture decision with a parse-time cost for
          every caller.
  #2207 - its own criteria demand a cross-platform architecture decision.

Three of these carried a stale "/rv is absent" line; in every case /rv was
never the actual gate, and that is now written down so it is not re-derived.

Author: robertvokac