feat(glossary): add optional paths.glossary standing-reading slot

Pins canonical nomenclature per project so terminology does not drift
and LLM-driven work reuses the established term instead of coining a
synonym each session. The glossary rides the existing standing-reading
mechanism — one optional path slot, no new delivery path.

Single-sourcing, to avoid cross-doc drift:
- `paths.glossary` row in profile-schema.md owns the "set => standing
  reading for every role; unset => no-op" semantics; agent-template.md
  and pipeline.md each carry one referencing sentence, not a restatement.
- glossary-convention.md owns the format (flat per-term blocks: canonical
  heading + Avoid line + <=2-sentence definition) and the boss
  record-reality-never-invent write-rule; boss/SKILL.md only points to it.
- glossary.md dogfoods the format on the plugin's own vocabulary
  (cycle, milestone, iteration, drift, hard-gate).

Write authority: user any time; boss autonomously but only to record
terms already in consistent use or to settle a drift it just resolved —
never to coin. All other roles are read-only consumers.

No executable surface; this repo has no test runner, so each task closed
on a grep presence-assertion against the file it touched. All eight gates
green (T1 3>=3, T2 5, T3 2, T4 1, T5 1, T6 1, T7 2, final sweep present).

Implements docs/specs/2026-05-31-glossary-integration-design.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/glossary.md

@@ -0,0 +1,35 @@
+# Glossary
+
+Canonical nomenclature for this project. Use the **canonical term**;
+never use a term under **Avoid**. If you need a concept that is not
+listed here, reuse the closest existing term — do not silently coin
+a new one. New entries are added only to record nomenclature already
+in consistent use; see `glossary-convention.md`.
+
+---
+
+### cycle
+**Avoid:** release, epic, round, sprint
+One round in the pipeline graph (design → plan → execute → review →
+close). Not the top-level container — that is a *milestone*.
+
+### milestone
+**Avoid:** epic, phase, big-ticket
+A tracker container spanning potentially many cycles; closes only
+when its promised work is complete and functional. A cycle close is
+never a milestone close.
+
+### iteration
+**Avoid:** sprint, story, step
+The default sub-unit of a cycle; one pass through the inner loop. A
+project may rename it via `vocabulary.subcycle`.
+
+### drift
+**Avoid:** divergence, rot, skew
+Accumulated mismatch between the codebase and its design ledger.
+Surfaced by the architect agent at audit, not by any synonym check.
+
+### hard-gate
+**Avoid:** checkpoint, barrier, blocker
+A pipeline point that forbids downstream work until an artefact
+exists and is approved (e.g. an approved spec before any plan).