rewrite(phase6): batch 12 — DISC/RELAY catalog re-derivation

[SoundMatt]

rewrite(phase6): batch 12 — DISC/RELAY catalog re-derivation

Part of the v3.0.0 ground-up rewrite (cpp-RCP #129, ROADMAP.md Phase 17),
branch rewrite/v3-from-c-rcp. Phase 6 (requirement catalog), batch 12 of 13.

Scope

discovery.hpp's REQ-DISC-* (c-RCP: 30 entries), adapt.hpp's REQ-RELAY-*
(c-RCP: 17 entries) -- 47 c-RCP entries total.

Major finding: DISC already far ahead of the catalog, RELAY needed real work

discovery.hpp/test_discovery.cpp already carried real fusa:req/bracket-tag
citations for nearly the full 001-030 range from an earlier untracked
pass (only 5 missing //fusa:req manifest lines for 025-028/030) --
almost entirely a catalog-side derivation. adapt.hpp/test_adapt.cpp only
covered cpp's own pre-rewrite REQ-RELAY-001-005 numbering; the real
c-RCP 006-017 range needed genuine investigation against c-RCP's
per-op field-table design vs cpp's simpler generic-RequestFn shape.

Id-collision pattern (same class as batches 6-11)

Both prefixes' pre-existing low-numbered ids were assigned before this
rewrite's "reuse c-RCP's exact id" convention took hold and collide
with unrelated, real c-RCP content at the same numerals (verified
directly, e.g. cpp's REQ-DISC-001 "Discovery request framing" vs
c-RCP's real REQ-DISC-001 "should_drop flags non-NTSCF subtype" --
unrelated). Filed as 14 id-collision gaps (DISC 001-009 x9, RELAY
001-005 x5) to .fusa-reqs-pending.json -- in every DISC case the real
c-RCP behavior turned out to already be correctly implemented+tested
under the matching numeral, only the catalog entry was stale/collided.

New catalog entries (29)

• DISC: 21 (010-030) -- genuinely implemented+tested already; 5 needed
  their missing //fusa:req manifest tag added (025-028, 030).
• RELAY: 8 (006, 008, 009, 010, 012, 014, 016, 017) -- genuinely
  implemented+tested, with text adapted to document where cpp's
  generic-RequestFn design diverges from c-RCP's per-op field table
  (no failure path on 006, no bound-kind check on 008/009, no
  transport/kind params on 012). 014/016/017 actually live in
  relay.hpp/rcp.hpp rather than adapt.hpp -- tagged in adapt.hpp per
  this repo's existing convention (001-005 already do the same), with
  test tags placed in test_relay.cpp where the real tests live. Added
  2 small missing tests (Channel::is_closed(), to_string(Protocol)
  uniqueness) to genuinely earn 002's and 016's claims.

Architecture-divergence gaps filed (4, RELAY only, deliberate not oversights)

REQ-RELAY-007 (no per-op opcode enum -- explicitly documented in
test_adapt.cpp's own header comment as intentionally unported),
REQ-RELAY-011 (no adapt-specific error category/strerror -- std::errc
reused instead), REQ-RELAY-013 (no RCP-namespaced SpecVersion alias --
single-namespace architecture has nothing to duplicate, c-RCP's two-
package split doesn't apply here), REQ-RELAY-015 (no manual caller
retain/refcount -- superseded by std::unique_ptr RAII, also explicitly
documented as unported in test_adapt.cpp).

No new entry (DISC or RELAY) carries severity:cybersecurity -- confirmed
via ci.yml/CYBERSECURITY.md that only cpp's existing (untouched)
REQ-DISC-001..009 are in the enumerated 72-id cybersecurity subset;
REQ-RELAY-* never appears there. sec-tested count unchanged at exactly
72.

Verification

Independently re-verified (the porting agent's own final step re-ran
the real pinned cpfusa v0.18.0 binary, not an approximating script --
the batch-11 lesson applied from the start this time): semantic
id-keyed diff confirms zero pre-existing entries modified/deleted,
exactly 29 new ids matching the report's breakdown exactly (DISC 21,
RELAY 8), zero duplicate ids. Independently re-ran the real cpfusa
binary myself against the merged worktree: testedRequirements ==
totalRequirements == 1105, cpfusa trace --gaps returns zero ids.
Confirmed sec-tested count holds at exactly 72/1105. Directly
spot-checked the REQ-DISC-001 collision claim and the REQ-RELAY-013
architecture-divergence gap text against the real diff -- both
accurate. Full tree rebuilt from scratch: 0 errors, 0 warnings, 58/58
ctest suites pass (100%).

.fusa-reqs.json: 1076 -> 1105 entries (+29, 11498 -> 11836 lines).
.fusa-reqs-pending.json: 123 -> 141 entries (+18, 1420 -> 1600 lines).
include/rcp/adapt.hpp: +19 lines (tags only). include/rcp/discovery.hpp:
+5 lines (tags only). tests/test_adapt.cpp: +5 lines (tags only).
tests/test_relay.cpp: +36 lines (tags + 2 new tests).

Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com