feat(ui): location picker in Bookmark tab (Workstream 7, #680)

Adds the starting-location picker as a sub-component of the Bookmark
tab detail view, per Araminta's spec and D-128's "culture implicit in
location" constraint. Fills the space W6 reserved below the CAREER /
CAPITAL data rows.

Picker structure:
- "STARTING LOCATION" section label (DIM_TEXT, 10px, all-caps).
- ScrollContainer min_height=80 → VBoxContainer of selectable items.
- Each item: Button with child VBox carrying the location name Label
  (PRIMARY_TEXT, 12px) and an optional culture tag Label (DIM_TEXT,
  10px, mouse_filter IGNORE per D-128). Culture label is NOT rendered
  when `allowed_locations_cultures[i]` is empty — no "Unknown"
  placeholder, the row just shrinks.

Behavior:
- Clicking a bookmark card auto-selects its default_location in the
  picker (handled via _selected_location_id + _update_location_selection).
- Clicking a location item updates _selected_location_id and re-gates
  the Start button (already checked in W6).
- Switching bookmarks rebuilds the picker list for the new
  allowed_locations; prior selection cleared.
- Parallel-array length mismatch defended: reads
  `cultures[i] if i < cultures.size() else ""` so a short cultures
  array won't crash rendering.

D-128 compliance:
- No culture dropdown or filter anywhere.
- Culture tag Label is strictly display: MOUSE_FILTER_IGNORE, no
  signal handlers.
- CharacterProfile carries only start_location_id; no culture_id.

Other: removes W6's placeholder "Starting Location: X" ImplantDataRow
since the picker supersedes it; separator before the picker preserved.

Verification:
- gdlint clean
- Headless parse + scanner check (widened per hardened pr-push skill):
  no new errors. Pre-existing autoload class_name noise filtered per
  CLAUDE.md.
- test_character_creation_sprint28 88/88, test_protocol 62/62,
  test_implant_* all green, test_client_p3 24/24,
  test_ui_framework_sprint15 54/54.

Workstream 8 (Skills tab stub content) lands next — #618 closes then.

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

client/ui/meta/screens/character_creation/character_creation.gd

@@ -273,12 +273,16 @@ var _appearance_active_idx: int = 0
 var _appearance_sub_btns: Array[Button] = []
 var _appearance_sub_sections: Array[Control] = []
 
-# --- Bookmark tab state (WS6) ---
+# --- Bookmark tab state (WS6/WS7) ---
 var _selected_bookmark_id: String = ""
 var _selected_location_id: String = ""
 var _bookmark_cards: Array[Button] = []
 var _bookmark_detail_panel: ImplantPanel = null
 var _bookmark_cards_vbox: VBoxContainer = null
+var _location_items: Array[Button] = []
+var _location_item_ids: Array[String] = []
+var _location_item_labels: Array[Label] = []
+var _location_vbox: VBoxContainer = null
 
 # --- Asset manifest (loaded once, replaces filesystem scanning) ---
 var _manifest: Dictionary = {}
@@ -739,6 +743,11 @@ func _update_bookmark_card_selection() -> void:
 
 func _refresh_bookmark_detail(bm: Dictionary) -> void:
 	_bookmark_detail_panel.clear()
+	_location_items.clear()
+	_location_item_ids.clear()
+	_location_item_labels.clear()
+	_location_vbox = null
+
 	if bm.is_empty():
 		_bookmark_detail_panel.add_component(
 			ImplantHeader.new("Select a Bookmark", "Choose your starting conditions")
@@ -757,9 +766,9 @@ func _refresh_bookmark_detail(bm: Dictionary) -> void:
 		ImplantDataRow.new("Starting Capital: %d tr" % int(capital), TEXT_COLOR)
 	)
 
-	var default_loc: String = bm.get("default_location", "")
-	if not default_loc.is_empty():
-		_bookmark_detail_panel.add_component(ImplantDataRow.new("Starting Location: " + default_loc, TEXT_DIM))
+	# Location picker (WS7) — replaces the single "Starting Location: X" DataRow
+	_bookmark_detail_panel.add_component(ImplantSeparator.new())
+	_build_location_picker(bm)
 
 	var flavor: String = bm.get("flavor", "")
 	if not flavor.is_empty():
@@ -771,6 +780,85 @@ func _update_start_btn_state() -> void:
 	_footer_start.disabled = _selected_bookmark_id.is_empty() or _selected_location_id.is_empty()
 
 
+func _build_location_picker(bm: Dictionary) -> void:
+	var allowed: Array = bm.get("allowed_locations", [])
+	var cultures: Array = bm.get("allowed_locations_cultures", [])
+
+	var section_lbl := Label.new()
+	section_lbl.text = "STARTING LOCATION"
+	section_lbl.add_theme_color_override("font_color", TEXT_DIM)
+	section_lbl.add_theme_font_size_override("font_size", 10)
+	section_lbl.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	_bookmark_detail_panel.add_component(section_lbl)
+
+	if allowed.is_empty():
+		return
+
+	var scroll := ScrollContainer.new()
+	scroll.custom_minimum_size = Vector2(0, 80)
+	scroll.size_flags_horizontal = Control.SIZE_FILL
+	_bookmark_detail_panel.add_component(scroll)
+
+	_location_vbox = VBoxContainer.new()
+	_location_vbox.size_flags_horizontal = Control.SIZE_FILL
+	_location_vbox.add_theme_constant_override("separation", 2)
+	scroll.add_child(_location_vbox)
+
+	for i in allowed.size():
+		var loc_id: String = allowed[i]
+		var culture: String = cultures[i] if i < cultures.size() else ""
+
+		var btn := Button.new()
+		btn.size_flags_horizontal = Control.SIZE_FILL
+		btn.flat = false
+		btn.focus_mode = Control.FOCUS_NONE
+		btn.pressed.connect(_on_location_selected.bind(loc_id))
+
+		var vbox := VBoxContainer.new()
+		vbox.mouse_filter = Control.MOUSE_FILTER_IGNORE
+		vbox.add_theme_constant_override("separation", 1)
+		vbox.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
+		btn.add_child(vbox)
+
+		var name_lbl := Label.new()
+		name_lbl.text = loc_id
+		name_lbl.add_theme_color_override("font_color", TEXT_COLOR)
+		name_lbl.add_theme_font_size_override("font_size", 12)
+		name_lbl.mouse_filter = Control.MOUSE_FILTER_IGNORE
+		vbox.add_child(name_lbl)
+
+		if not culture.is_empty():
+			var culture_lbl := Label.new()
+			culture_lbl.text = culture
+			culture_lbl.add_theme_color_override("font_color", TEXT_DIM)
+			culture_lbl.add_theme_font_size_override("font_size", 10)
+			culture_lbl.mouse_filter = Control.MOUSE_FILTER_IGNORE
+			vbox.add_child(culture_lbl)
+
+		_location_vbox.add_child(btn)
+		_location_items.append(btn)
+		_location_item_ids.append(loc_id)
+		_location_item_labels.append(name_lbl)
+
+	_update_location_selection()
+
+
+func _on_location_selected(loc_id: String) -> void:
+	_selected_location_id = loc_id
+	_update_location_selection()
+	_update_start_btn_state()
+
+
+func _update_location_selection() -> void:
+	for i in _location_items.size():
+		var selected: bool = (i < _location_item_ids.size() and _location_item_ids[i] == _selected_location_id)
+		_set_item_selected(_location_items[i], selected)
+		if i < _location_item_labels.size() and is_instance_valid(_location_item_labels[i]):
+			_location_item_labels[i].add_theme_color_override(
+				"font_color", HIGHLIGHT_COLOR if selected else TEXT_COLOR
+			)
+
+
 # =============================================================================
 # Tab: Body (Task #2)
 # =============================================================================