docs(overrides): user guide for opt-in icon packs

The only doc for the icon-pack override was a comment in the downstream
template. Add an "Icon pack" subsection to docs/OVERRIDES.md § Appearance
(the user-facing appearance-customization doc): the
`nomarchy-theme-sync set icons "<name>"` command, why only Papirus ships
by default (~1 GiB; extra packs opt-in), a known-packs table, and that
the choice is sticky across `apply` (presets carry no icon field).

Example names verified by building all four packs and listing their real
theme directories — corrected Qogir to its capitalized Qogir-Dark/Light
(a lowercase name silently falls back to hicolor). Hibernation needs no
new doc (README swapfile note + MIGRATION.md runbook + Power-menu row).

Verification: V0 (docs-only); command + variant names checked live.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/JOURNAL.md

@@ -17,6 +17,21 @@ Template:
 
 ---
 
+## 2026-07-10 — Icon overrides: user-facing docs (OVERRIDES.md)
+- **Task:** Bernardo asked whether the session's features need user docs.
+- **Did:** Hibernation already covered (README swapfile line, MIGRATION.md
+  runbook, discoverable Power-menu row) — no gap. Icons had one: the only
+  doc was the template comment. Added an "Icon pack" subsection to
+  `docs/OVERRIDES.md` § Appearance — `nomarchy-theme-sync set icons "<name>"`,
+  the known-packs table, the ~1 GiB/opt-in rationale, and that the choice is
+  sticky across `apply` (presets carry no icon field; verified `deep_merge`).
+- **Verified:** command path confirmed (`cmd_set` writes any dotted key;
+  `icons` is a schema key). **Built all 4 packs and listed real theme dirs**
+  to fix the examples — caught Qogir using capital `Qogir-Dark`/`Light`
+  (lowercase would silently fall back to hicolor). Docs-only (V0).
+- **Pending:** none.
+- **Next suggestion:** NEXT #76 `[blocked:hw]`; LATER/QA-sweep next.
+
 ## 2026-07-10 — Icon themes: opt-in cross-pack overrides (no default bloat)
 - **Task:** LATER "per-theme icon overrides / more icon packs". Recon found
   papirus is already ~1 GiB and ships only Papirus/Dark/Light (no free