docs(roadmap): add Phase 8.8 — language-specific analysis reference map (34 languages)

Adds section 8.8 to the Phase 8 roadmap covering every language codegraph
supports. For each of the 34 languages (grouped into 13 families including
HCL/Terraform), documents:

- State-of-the-art call-graph / points-to analysis tools (Jelly-equivalents)
- Published precision/recall figures with paper/benchmark citations
- Codegraph's current gap vs. those tools
- Concrete adoption candidates (techniques to implement)
- Benchmark suites and fixture sources with license annotations

Fixture acquisition guide added to the 8.8 intro: MIT/Apache/BSD/CC-BY
fixtures may be committed directly; GPL fixtures are reference-only; academic
suites with no license should be derived by running the tool, not copied.

Cross-references 8.6 (CI gate) to extend benchmarking beyond Jelly/ACG to
all 34 languages using the reference map.

Author: carlos-alm