v1.0.8 — Space derivation fix

Fix: space derivation now walks to project root instead of taking the last 2 path components.

Previously a single project was fragmented into multiple spaces whenever the user cd'd into subdirectories (e.g. ~/Desktop/Oasis_App, frontend/android, Oasis_App/backend all resolved to distinct spaces). This silently broke Level 1 stigmergic reinforcement — a textbook K-fragmentation confirmed in primordial-soup exp_task_diversity (K=5 → 99% drop in strong traces).

New service::derive_project_space(path) walks ancestors looking for:

1. .git (dir or file) — repo root
2. Common project manifests (Cargo.toml, package.json, pyproject.toml, go.mod, pom.xml, build.gradle[.kts])
3. Legacy fallback: last 2 path components

Migration: none. Old traces keep their old space labels and fade under the 168h decay; new traces write under the corrected identifier.

6 new unit tests. Full suite (380+ tests) passing.