[Docs] Populate architecture, design, and roadmap docs from thesis/current code

[Darkroom4364]

Context:
The thesis PDF contains the real design narrative, but the Markdown docs in the repository are currently empty:

• docs/architecture.md
• docs/design.md
• docs/roadmap.md

This supersedes the closed historical docs issue #30 for the current codebase state.

Proposed scope:

• Convert the thesis architecture/design sections into concise repo-native docs.
• Document the current Go server, Rust agent, static UI, payload builder, OPSEC engine, and SOCKS5/pivot modules.
• Clearly mark prototype-only or partially wired features.
• Add a practical roadmap that separates stabilization, safety hardening, feature completion, testing, and research ideas.

Acceptance criteria:

• All three Markdown docs are non-empty and reflect the current tree.
• Claims in docs match implementation status.
• README links to the new docs.
• Roadmap avoids mixing foundational cleanup with long-range research work.

[Darkroom4364]

Completed via #92 and merged into dev. The docs now populate architecture, design, and roadmap content from the thesis/current code state, README links to the docs, and the roadmap separates stabilization from longer-range research work.