Complete Story 3.3: Preset Import & Export

Implements FR-19: Preset import/export as JSON

New Files:
- src/core/PresetImportExportManager.js - Core logic for export/import with merge/replace
- src/ui/gm/PresetExportDialog.js - Export dialog with file download
- src/ui/gm/PresetImportDialog.js - Import dialog with file picker, preview, merge/replace
- templates/preset-export.hbs - Export dialog template
- templates/preset-import.hbs - Import dialog template
- styles/components/_preset-import-export.less - Dialog styles
- tests/unit/core/PresetImportExportManager.test.js - 38 unit tests
- _bmad-output/implementation-artifacts/3-3-preset-import-and-export.md - Story file

Modified Files:
- src/ui/gm/DirectorsBoard.js - Added export/import button handlers
- templates/directors-board.hbs - Added Export/Import buttons to footer
- styles/scrying-pool.less - Added stylesheet import
- lang/en.json - Added localization strings for new UI
- _bmad-output/implementation-artifacts/sprint-status.yaml - Story status: review

Features:
- Export all presets from current scene as JSON file
- Import presets with merge (add new, skip duplicates) or replace (overwrite all) modes
- Preview of presets before import with validation status
- Confirmation dialog for replace mode to prevent data loss
- Comprehensive error handling and validation
- All ACs satisfied (AC-9 deferred for README docs)

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

lang/en.json

@@ -45,7 +45,9 @@
       "openButton": "Open Director's Board",
       "footer": {
         "savePreset": "Save Preset…",
-        "loadPreset": "Load Preset…"
+        "loadPreset": "Load Preset…",
+        "exportPresets": "Export Presets…",
+        "importPresets": "Import Presets…"
       },
       "bulk": {
         "showAll": "Show All",
@@ -76,6 +78,92 @@
         "name": "Spotlight Focused Participant",
         "hint": "Shows the focused participant and hides all others"
       }
+    },
+    "presets": {
+      "save": {
+        "saveButton": "Save",
+        "cancelButton": "Cancel",
+        "title": "Save Scene Preset",
+        "nameLabel": "Preset Name",
+        "namePlaceholder": "Enter a name for this camera layout"
+      },
+      "load": {
+        "loadButton": "Load",
+        "cancelButton": "Cancel",
+        "title": "Load Scene Preset",
+        "emptyMessage": "No presets saved yet. Use 'Save Preset' to create one."
+      },
+      "notifications": {
+        "saved": "Scene preset '{name}' saved.",
+        "applied": "Scene preset '{name}' applied.",
+        "scene-applied": "Scene changed: camera layout updated"
+      }
+    },
+    "presetExport": {
+      "title": "Export Scene Presets",
+      "description": "Download all scene presets as a JSON file that can be imported into another world.",
+      "scene": "Scene",
+      "presetCount": "Presets",
+      "filename": "Filename",
+      "export": "Export",
+      "cancel": "Cancel",
+      "exporting": "Exporting…",
+      "exportSuccess": "Scene presets exported successfully.",
+      "exportFailed": "Failed to export presets"
+    },
+    "presetImport": {
+      "title": "Import Scene Presets",
+      "description": "Upload a JSON file containing scene presets to add to this scene.",
+      "selectFile": "Select File",
+      "chooseFile": "Choose a JSON file…",
+      "importMode": "Import Mode",
+      "importModeMerge": "Merge",
+      "importModeReplace": "Replace",
+      "importModeMergeHint": "Add new presets, skip duplicates",
+      "importModeReplaceHint": "Delete all existing presets and import new ones",
+      "previewTitle": "Preview",
+      "previewWillImport": "Will import",
+      "previewWillSkip": "Will skip (already exists)",
+      "import": "Import",
+      "confirmReplace": "Replace All",
+      "cancel": "Cancel",
+      "importing": "Importing…",
+      "importFailed": "Failed to import presets",
+      "selectFileFirst": "Please select a file first",
+      "existingPresetsWarning": "This scene has {existingPresetCount} existing preset(s).",
+      "replaceConfirmation": "This will delete all {existingPresetCount} existing preset(s) and replace them with the imported ones. This cannot be undone."
     }
+  },
+  "SCRYING_POOL": {
+    "ExportPresetsTitle": "Export Scene Presets",
+    "ExportPresetsDescription": "Download all scene presets as a JSON file that can be imported into another world.",
+    "Scene": "Scene",
+    "PresetCount": "Presets",
+    "Filename": "Filename",
+    "Export": "Export",
+    "Cancel": "Cancel",
+    "Exporting": "Exporting…",
+    "ExportSuccess": "Scene presets exported successfully.",
+    "ExportFailed": "Failed to export presets",
+    "ImportPresetsTitle": "Import Scene Presets",
+    "ImportPresetsDescription": "Upload a JSON file containing scene presets to add to this scene.",
+    "SelectFile": "Select File",
+    "ChooseFile": "Choose a JSON file…",
+    "ImportMode": "Import Mode",
+    "ImportModeMerge": "Merge",
+    "ImportModeReplace": "Replace",
+    "ImportModeMergeHint": "Add new presets, skip duplicates",
+    "ImportModeReplaceHint": "Delete all existing presets and import new ones",
+    "PreviewTitle": "Preview",
+    "PresetExistsWillBeSkipped": "Already exists - will be skipped",
+    "Import": "Import",
+    "ConfirmReplace": "Replace All",
+    "Importing": "Importing…",
+    "ImportFailed": "Failed to import presets",
+    "SelectFileFirst": "Please select a file first",
+    "ExistingPresetsWarning": "This scene has {existingPresetCount} existing preset(s).",
+    "ReplaceConfirmation": "This will delete all {existingPresetCount} existing preset(s) and replace them with the imported ones. This cannot be undone.",
+    "UnknownScene": "Unknown Scene",
+    "firstBadgeEncounter": "First Badge Encounter"
   }
 }