docs(eigenda): remove outdated v1 documentation and Blazar release notes

EigenDA V2 (Blazar) has been live on mainnet since June 2025, with V1
now fully deprecated. This cleanup removes:

**Removed Files:**
- Blazar release notes and migration guide (migration timeline passed)
- Disperser API v1 documentation (4 files)
- V1 integration guides (proxy v1, golang client v1)
- V1 quick-start guide
- Deprecated system requirements
- Orphaned static assets (proxy-v1.png, v2-1.png)

**Updated Files:**
- operator-guides/overview.md: Removed v1 migration section
- networks/mainnet.md: Removed deprecated V1 specs section
- networks/hoodi.md: Simplified to V2-only specs
- eigenda-proxy.md: Removed broken v1 docs link
- integrations-overview.md: Removed broken blazar.md link

V1 references in rollup guides (OP Stack, Orbit) are retained as they
document migration paths for existing deployments that still need to
retrieve legacy V1 blobs.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: mmurrs