fix(docs): align GROUNDS row in TYPE_DUPLICATION_MAP with canonical Option R-3 mapping

PR #374 review (chatgpt-codex-connector P2 catch): TYPE_DUPLICATION_MAP §13
mapped GROUNDS → InferenceType::Abduction, but the cited canonical source
(.claude/knowledge/causal-edge-64-synergies-and-pr-trajectory.md §6.3
Option R-3) groups BECOMES / GROUNDS / RELATES → InferenceType::Synthesis.

If a future sprint-12 transcoder were implemented from this summary, GROUNDS
edges would commit with a different InferenceType than the canonical design —
silent drift across two derivative references.

Fix: change GROUNDS row to Synthesis matching the canonical source. Added an
inline note that the semantic question (Synthesis vs Abduction for
"foundational basis = abductive justification") is an open design question
for the sprint-12+ transcoder spec — preserving the bot's catch as
architectural future work rather than just hiding it.

No other rows audited as drifted: CAUSES (Deduction), SUPPORTS (Revision+),
REFINES (Abduction), ABSTRACTS (Induction), RELATES (Synthesis), CONTRADICTS
(Revision-), BECOMES (Synthesis) all match the synergies doc.

https://claude.ai/code/session_01UwJuKqP828qyX1VkLgGJFS

Author: claude

docs/TYPE_DUPLICATION_MAP.md

@@ -189,7 +189,7 @@ These represent **different cognitive operations** rendered into the same u64 re
 - CAUSES → `InferenceType::Deduction` (forward chain)
 - SUPPORTS → `InferenceType::Revision` positive (truth corroboration)
 - REFINES → `InferenceType::Abduction` (specialization)
-- GROUNDS → `InferenceType::Abduction` (foundational basis)
+- GROUNDS → `InferenceType::Synthesis` (foundational basis — grouped with BECOMES + RELATES per canonical source; whether GROUNDS deserves a dedicated `InferenceType::Abduction` mapping for "foundational basis = abductive justification" semantics is an open design question for the sprint-12+ transcoder spec)
 - ABSTRACTS → `InferenceType::Induction` (upward generalization)
 - RELATES → `InferenceType::Synthesis` (lateral relation)
 - CONTRADICTS → `InferenceType::Revision` negative (refutation, lowers c)