Path-scoped auto-discovery + dynamic context injection

[harrymunro]

Summary

Add paths: [".nelson/**"] glob activation so Nelson auto-activates when a .nelson/ directory is detected. On activation, inject project-specific context (mission history summary, active ships, hull integrity state) as a dynamic briefing prefix.

Motivation

Every Nelson mission currently starts from a blank slate. The admiral has no awareness of past missions, active state, or project context until it manually reads files. Claude Code's skill system already supports both paths: scoping and dynamic context injection via the !`command` syntax — Nelson just doesn't use them.

Detailed Design

Path-Scoped Activation

Add to SKILL.md frontmatter:

paths:
  - ".nelson/**"

This causes Nelson to auto-activate when any file in .nelson/ is detected in the working directory, supporting:

• Automatic session resumption when returning to a project with active missions
• Project-aware Nelson without explicit /nelson invocation

Dynamic Context Injection

Add to SKILL.md body (top, before Step 1):

```!
python3 {skill-dir}/scripts/nelson-data.py status --mission-dir $(ls -td .nelson/missions/*/ 2>/dev/null | head -1) 2>/dev/null || echo "No active missions"
```

This injects current fleet status as a briefing prefix before any instruction is processed:

• Active mission count and status
• Ship roster and hull integrity
• Pending tasks and blockers
• Last checkpoint summary

Enhanced Status Output

Extend nelson-data.py status to produce a compact, context-efficient briefing:

NELSON FLEET STATUS
Mission: 2026-04-08_201214 (underway)
Progress: 3/5 tasks complete | 1 blocked
Ships: HMS Argyll (Green 82%) | HMS Kent (Amber 65%) | HMS Daring (completed)
Last checkpoint: 2 (12 min ago)
Budget: 45% consumed

Rationale

• HMS Diamond identified both path-scoped activation and dynamic context injection as underused primitives
• HMS Astute identified "every mission starts from scratch" as a key gap
• These two features together solve the cold-start problem with existing platform capabilities
• Context injection from mission state is unique to Nelson's structured data layer

Effort Estimate

Small

Impact

High — eliminates cold-start overhead and makes Nelson project-aware from the first token

Dependencies

None — Tier 1 item. Uses existing nelson-data.py status infrastructure.