feat: target photo uploads on range session lines

[crzykidd]

Deferred from the v0.3.0 range release (PRD §10.2 / §10.8). Attach target photos to individual range session lines.

Scope

• Add a target_photo column (or photo table) for range_session_lines in a new migration — no schema column exists yet.
• Upload UI on the range session line, image storage under /data/uploads/, and image management/lightbox screens.
• Reuse the firearm-photo pipeline where sensible (auto-resize, thumbnail, EXIF orientation, auth-gated streaming, inclusion in zip backups).

Notes

• Firearm photos shipped in v0.3.0 and provide a working pattern to follow (see PRD §10.1).

Source: PRD §10.8 (deferred from v0.3.0).