feat(tooling): add atlas-update-field and atlas-commit-and-sync scripts

atlas-update-field: update system-level fields across star_systems,
system_gates, and system_history tables with field whitelist.
atlas-commit-and-sync: full per-system pipeline (verify → wipe → commit
→ sync-wiki → git commit). Updated atlas SKILL.md with new commands.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.claude/skills/atlas/SKILL.md

@@ -99,6 +99,28 @@ Reads `habitable_planet_count`, `inhabited_planet_count`, `gas_giant`,
 Creates: planets (inhabited first), gas giants, asteroid belts, oort cloud per
 system, horizon station per oort cloud. Skips systems that already have bodies.
 
+### Update a system-level field
+```bash
+tooling/atlas-update-field "GJ 687" settlement_wave wave_3
+tooling/atlas-update-field "GJ 53A" star_type G
+```
+Updates a whitelisted field in systems.db. Auto-detects the correct table
+(`star_systems`, `system_gates`, or `system_history`). Inserts a row in
+child tables if one doesn't exist yet.
+
+Whitelisted fields: `star_type`, `spectral_class`, `proper_name`,
+`geographic_sector`, `habitable_planet_count`, `inhabited_planet_count`,
+`gate_topology`, `aperture_count`, `hop_distance_from_gateway`,
+`settlement_wave`, `founding_culture_primary`, `founding_culture_secondary`.
+
+### Commit and sync a single system
+```bash
+tooling/atlas-commit-and-sync "GJ 105A" east_reach
+```
+Full pipeline: verify proposal → wipe existing data (if any) → commit to DB
+→ sync wiki → git add + git commit. Second argument is the corridor tag for
+the commit message (defaults to `east_reach`).
+
 ## Body ID Naming Convention
 
 ```