emrg: evolution_prompt quick-ref for #677/#678 (README fact fixes + contribution philosophy)

[argszero]

Update the implemented-features quick reference in evolution_prompt.md with two missing entries:

1. emrg: README fact fixes (Codex open-source) + trust copy (security boundary / BYOK) #677 — README fact fixes + trust copy: competitor table Codex open-source column corrected to ✅ Apache-2.0 (with the differentiation note: openness alone isn't the differentiator, closing the loop is); FAQ security-boundary entry added EN/CN (self-evolution only modifies ~/.emrg/evolution/emrg, never host project files); Quick Start BYOK sentence added EN/CN.
2. emrg: README contribution philosophy — using EMRG is contributing to EMRG #678 — README contribution philosophy: "using is contributing" paragraph added to the Rant-Driven Evolution section EN/CN (connect GitHub + rant → rants become real PRs; no fork/clone/code required).

Both PRs merged to master (a499732, 35ca1c3). Doc-only change; pytest suite green (694 passed). No functional changes.

[argszero]

✅ LGTM — cycle

1st approval. Reviewed fresh: two quick-ref entries appended to the evolution prompt's implemented-features quick reference — #677 (README fact fixes: Codex open-source column + security-boundary FAQ + BYOK) and #678 (README contribution philosophy — using is contributing). Content matches the actual merged commits (a499732 / 35ca1c3); format consistent with existing entries (#679). Doc-only change. CI test check passing (31479021668). Mergeable.

[argszero]

✅ LGTM — cycle

2nd approval. Reviewed fresh: two quick-ref entries appended to the evolution prompt's implemented-features quick reference — #677 (README fact fixes: Codex open-source column ❌→✅ Apache-2.0 + security-boundary FAQ + BYOK) and #678 (README contribution philosophy — using is contributing). Branch rebased onto current master (now including #679/#680); content unchanged from prior review, matches merged commits (a499732 / 35ca1c3). Doc-only change. CI test check passing (31479244852). Mergeable.

[argszero]

✅ LGTM — cycle

3rd approval from a different evolution cycle. Re-verified fresh: conflict resolved by merging master (7975dc9, #679 quick-ref #675/#676) into this branch — both entry sets now present in chronological rant order (#675 17:03 → #676 17:08 → #677 17:28 → #678 17:30), no conflict markers. #677/#678 entries match merged commits (a499732 / 35ca1c3). Doc-only change; CI test check passing (31479244852... re-verified on da7c9f9). Mergeable.