Scope registry deduplication to warp --new

[sjquant]

Why

gji warp --new should treat duplicate registry rows for the same repo as one target, but regular gji warp navigation still needs the raw registry so every registered entry remains discoverable.

Changes

• keep loadRegistry() returning raw entries instead of globally deduplicating them
• deduplicate canonical repo paths only inside gji warp --new before target repo selection
• preserve alias-path collapse during registerRepo() writes so symlink and real-path variants do not accumulate
• add regression coverage for raw registry loading, warp --new duplicate handling, and alias-path registration cleanup