docs: P8 vocabulary governance + WSL run tribal knowledgedev

- AGENTS.md §4 'Naming & vocabulary': wire to GLOSSARY.md (P8 — never coin a
  synonym for an existing concept; propose new terms, don't coin silently).
- AGENTS.md §8 'Tribal knowledge (notes/)': establish notes/<topic>.md as the
  non-inferable-knowledge store with the P6 test.
- Rename study_segment_seek_target -> study_portion_seek_target ('segment' was
  a glossary-proscribed synonym for 'speaking portion'); fix 'Section nav' /
  'jump to start' comments to canonical terms (portion nav / seek).
- notes/wsl-arch-razer-run.md: how to run the desktop app under WSLg on the
  Arch/Razer dev machine (the LIBGL_ALWAYS_INDIRECT segfault trap, required
  env vars, GPU driver options).

1 files changed, 3 insertions, 3 deletions

diff --git a/src/layout_editor.c b/src/layout_editor.c
index 0a40c59..bffc9c9 100644
--- a/src/layout_editor.c
+++ b/src/layout_editor.c
@@ -54,7 +54,7 @@ void layout_editor_draw(const char *exePath, UILayout *layout)
            Later checks overwrite earlier ones if they overlap —
            priority goes to elements drawn last / on top. */
 
-        /* 6: Section nav buttons (two circles) */
+        /* 6: Portion nav buttons (two circles) */
         {
             float secPrevX = layout->secNavX - 65.0f;
             float secNextX = layout->secNavX + 65.0f;
@@ -167,7 +167,7 @@ void layout_editor_draw(const char *exePath, UILayout *layout)
             layout->smartPlayX = mouse.x - dragOffsetX;
             layout->smartPlayY = mouse.y - dragOffsetY;
             break;
-        case 6: /* Section nav */
+        case 6: /* Portion nav */
             layout->secNavX = mouse.x - dragOffsetX;
             layout->secNavY = mouse.y - dragOffsetY;
             break;
@@ -253,7 +253,7 @@ void layout_editor_draw(const char *exePath, UILayout *layout)
         draw_label("Play", r, f, borderColor);
     }
 
-    /* --- 6: Section nav buttons --- */
+    /* --- 6: Portion nav buttons --- */
     {
         Color f = (dragIndex == 6) ? highlightColor : fillColor;
         float secBtnRadius = 35.0f;