feat: Add floating sidebar navigation and dark theme support

- Add floating pill-shaped sidebar with navigation icons
- Implement dark/light theme toggle with localStorage persistence
- Update all figure factories for transparent backgrounds
- Use carto-darkmatter map style for choropleths
- Add methodology link button to Toronto dashboard header
- Add back to dashboard button on methodology page
- Remove social links from home page (now in sidebar)
- Update CLAUDE.md to Sprint 7

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

portfolio_app/pages/home.py

@@ -2,7 +2,6 @@
 
 import dash
 import dash_mantine_components as dmc
-from dash_iconify import DashIconify
 
 dash.register_page(__name__, path="/", name="Home")
 
@@ -52,19 +51,6 @@ PROJECTS = [
     },
 ]
 
-SOCIAL_LINKS = [
-    {
-        "platform": "LinkedIn",
-        "url": "https://linkedin.com/in/leobmiranda",
-        "icon": "mdi:linkedin",
-    },
-    {
-        "platform": "GitHub",
-        "url": "https://github.com/leomiranda",
-        "icon": "mdi:github",
-    },
-]
-
 AVAILABILITY = "Open to Senior Data Analyst, Analytics Engineer, and BI Developer opportunities in Toronto or remote."
 
 
@@ -160,27 +146,6 @@ def create_projects_section() -> dmc.Paper:
     )
 
 
-def create_social_links() -> dmc.Group:
-    """Create social media links."""
-    return dmc.Group(
-        [
-            dmc.Anchor(
-                dmc.Button(
-                    link["platform"],
-                    leftSection=DashIconify(icon=link["icon"], width=20),
-                    variant="outline",
-                    size="md",
-                ),
-                href=link["url"],
-                target="_blank",
-            )
-            for link in SOCIAL_LINKS
-        ],
-        justify="center",
-        gap="md",
-    )
-
-
 def create_availability_section() -> dmc.Text:
     """Create the availability statement."""
     return dmc.Text(AVAILABILITY, size="sm", c="dimmed", ta="center", fs="italic")
@@ -193,7 +158,6 @@ layout = dmc.Container(
             create_summary_section(),
             create_tech_stack_section(),
             create_projects_section(),
-            create_social_links(),
             dmc.Divider(my="lg"),
             create_availability_section(),
             dmc.Space(h=40),