feat(content): migrate line IDs to NPC-scoped namespace (D-035)

Line IDs in all dialogue and monologue pool files renamed from the
old location-scoped format (e.g. the-terminal_d_039) to the new
NPC-scoped format (e.g. kael-davan_d_001) per the D-035 Sprint 15
amendment.

Changes:
- 20 dialogue pool files across 3 locations renamed
- 14 monologue pool files (detective + smuggler) renamed
- Schema descriptions updated in dialogue/monologue schema files
- Authoring style guide and design docs updated with new examples
- Multi-location NPCs (kael-davan, pc-detective, pc-smuggler) given
  globally unique cross-file sequences to satisfy XREF uniqueness check

The location-scoped scheme already caused a collision (the-terminal_d_039
appearing in multiple NPC files) and would not scale to procedurally
generated NPC populations (D-029). Zero content changes — pure ID
substitution.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

content/_schema/dialogue-line.schema.json

@@ -10,7 +10,7 @@
     "id": {
       "type": "string",
       "pattern": "^[a-z][a-z0-9-]*_(d|m)_[0-9]{3}$",
-      "description": "Stable machine-parseable line ID: {template}_{d|m}_{###}. d = dialogue, m = monologue."
+      "description": "Stable machine-parseable line ID: {npc-slug}_{d|m}_{###} (e.g. kael-davan_d_001, pc-detective_m_d_001). d = dialogue, m = monologue. NPC-scoped per D-035 Sprint 15 amendment — each NPC has an independent sequence starting at _001."
     },
     "text": {
       "type": "string",

content/_schema/dialogue-pool.schema.json

@@ -32,7 +32,7 @@
         "id": {
           "type": "string",
           "pattern": "^[a-z][a-z0-9-]*_d_[0-9]{3}$",
-          "description": "Stable line ID: {location_slug}_d_{###}"
+          "description": "Stable line ID: {npc-slug}_d_{###} (e.g. kael-davan_d_001). NPC-scoped per D-035 Sprint 15 amendment — each NPC has an independent sequence starting at _001."
         },
         "text": {
           "type": "string",

content/_schema/monologue-pool.schema.json

@@ -32,7 +32,7 @@
         "id": {
           "type": "string",
           "pattern": "^[a-z][a-z0-9-]*_m_[sd]_[0-9]{3}$",
-          "description": "Stable line ID: {location_slug}_m_{s|d}_{###}. s = smuggler, d = detective."
+          "description": "Stable line ID: {npc-slug}_m_{s|d}_{###} (e.g. pc-smuggler_m_s_001, pc-detective_m_d_001). s = smuggler, d = detective. NPC-scoped per D-035 Sprint 15 amendment — each NPC has an independent sequence starting at _001."
         },
         "text": {
           "type": "string",