♻️ Drop the last duplicated prose from development/

The GitHub Flow description and the type-first enforcement sentence still
appeared in both CONTRIBUTING.md and development/. development/ now carries only
the context and rationale that is not in CONTRIBUTING.md.

development/testing.md

@@ -31,14 +31,6 @@ written before the runtime assertion, and both before the implementation.
 - Testing the type only: it would not catch handler wiring, `exhaustive()`
   throwing, or the `otherwise` fallback (see `src/index.test.ts`).
 
-## Enforcement
-
-Type-first is also enforced structurally: `npm test` runs `check:tsc` before the
-test runner, so a wrong type can never be papered over by a passing assertion.
-Per [AGENTS.md § Never do](../AGENTS.md#never-do), reach green honestly — fix the
-types so both the type check and the runtime assertion pass, never suppress the
-ones you can't make pass.
-
 The runner is `node --test --strip-types "src/**/*.test.ts"` and the tiers are
 listed in
 [CONTRIBUTING.md § Development commands](../CONTRIBUTING.md#development-commands).

development/workflow.md

@@ -7,15 +7,12 @@ are shaped the way they are.
 
 ## Branching model
 
-**GitHub Flow (single-developer).** Every change — feature, fix, refactor —
-branches off `main` and is merged back via a local commit. There is no pull
-request workflow on Gitea yet: collaborative review through the Gitea UI is not
-in place, so Gitea is the lab. When something is tested and ready for
-production it will be promoted to GitHub.
-
 The contributor-facing steps are in
-[CONTRIBUTING.md § Branching model](../CONTRIBUTING.md#branching-model); what
-follows is why the front doors exist and what was rejected.
+[CONTRIBUTING.md § Branching model](../CONTRIBUTING.md#branching-model). Two
+bits of context behind the model: collaborative review through the Gitea UI is
+not in place, so Gitea is the lab; and the project will be promoted to GitHub
+once it is tested and ready for production. What follows is why the front doors
+exist and what was rejected.
 
 #### Decision (2026-09)