feat(scaffold): add unified-gated-adapter + SSE + *-regen.yml (standards#89 sub-issue 1) (#12)

Scaffolded repos now get two new generated files:

1. `.github/workflows/<name>-regen.yml` — central regeneration trigger that
   fires the boj-server cartridge (`<name>-mcp/invoke`) instead of hand-
   committing artifacts.  Fire-and-forget until gateway tier-2 ships
   (continue-on-error with `by-design:` annotation for R4 lint compliance).
   Pattern source: k9iser-regen.yml merged into rsr-template-repo#58 /
   v3-templater#76 / reposystem#52.

2. `adapter/<name>_adapter.zig` — unified transaction-gated adapter (ONE
   loopback listener, protocol-routed REST + SSE + GraphQL + gRPC-compat →
   single gated dispatch → one Zig ABI).  Replaces the ssg-era 3-parallel-
   port anti-pattern.  Every request passes the transaction gate mirroring
   the Idris2 `exposureSatisfied` contract before dispatch.  4 gate truth-
   table tests verify the Zig mirror matches the Idris2 source-of-truth.
   Pattern source: k9iser_adapter.zig, boj-server#73.

Tests: 33 total (24 unit + 9 integration); all green.  File count
threshold updated to ≥22.  Files-written-to-disk test asserts both new
paths.

Refs hyperpolymath/standards#89

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath