merge: resolve conflicts with origin/main

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ARCHITECTURE.md

@@ -210,12 +210,13 @@ This is structurally sound — if a command exists in code, it appears in docs.
 
 ### The preamble
 
-Every skill starts with a `{{PREAMBLE}}` block that runs before the skill's own logic. It handles four things in a single bash command:
+Every skill starts with a `{{PREAMBLE}}` block that runs before the skill's own logic. It handles five things in a single bash command:
 
 1. **Update check** — calls `gstack-update-check`, reports if an upgrade is available.
 2. **Session tracking** — touches `~/.gstack/sessions/$PPID` and counts active sessions (files modified in the last 2 hours). When 3+ sessions are running, all skills enter "ELI16 mode" — every question re-grounds the user on context because they're juggling windows.
 3. **Contributor mode** — reads `gstack_contributor` from config. When true, the agent files casual field reports to `~/.gstack/contributor-logs/` when gstack itself misbehaves.
 4. **AskUserQuestion format** — universal format: context, question, `RECOMMENDATION: Choose X because ___`, lettered options. Consistent across all skills.
+5. **Search Before Building** — before building infrastructure or unfamiliar patterns, search first. Three layers of knowledge: tried-and-true (Layer 1), new-and-popular (Layer 2), first-principles (Layer 3). When first-principles reasoning reveals conventional wisdom is wrong, the agent names the "eureka moment" and logs it. See `ETHOS.md` for the full builder philosophy.
 
 ### Why committed, not generated at runtime?