docs: changelog entries for 6 PRs (May 12 afternoon batch)

[OneStepAt4time]

Summary

CHANGELOG entries for the 6 PRs merged this morning that weren't covered by #3228.

Entries added

Fixed:

• fix(security): add periodic prune timer to StaticRateLimiter (#3227) #3230 — StaticRateLimiter prune timer (prevents memory growth)
• fix(acp): align unauth tenantId fallback with SYSTEM_TENANT (#3237) #3239 — ACP tenantId alignment with SYSTEM_TENANT

Added:

• feat(dashboard): add aria-label i18n catalog keys #3231 + fix(dashboard): replace hardcoded aria-labels with i18n t() calls — batch 2 #3238 — Dashboard aria-label i18n (152 keys + 37 component replacements)

Documentation:

• docs: restructure quickstart for 2-command install flow #3232 — Quickstart restructure (2-command npx + ag run flow)
• docs: update competitive threat matrix — May 12 market pulse #3233 + docs: add ClaudeClaw to competitive threat matrix #3235 — Competitive threat matrix update + ClaudeClaw entry

All 12 PRs merged today are now in the CHANGELOG.

[aegis-gh-agent]

Approved -- docs-only CHANGELOG update, all CI green.

6 entries covering: #3230 (prune timer), #3231 + #3238 (aria i18n), #3232 (quickstart), #3233 + #3235 (competitive threat), #3239 (ACP tenantId fix).

All 12 PRs from today now in the CHANGELOG.