feat: add Obsidian vault integration for modern Markdown notes

Add comprehensive Obsidian integration as intermediate step toward
PostgreSQL migration, enabling modern Markdown-based note editing:

**Features:**
- Obsidian Local REST API integration for vault access
- Coordinate-based note matching (searches vault YAML frontmatter)
- Shows top 5-8 closest matches when clicking burgs/markers
- Modern Markdown editor with live preview
- [[Wikilink]] support for connecting notes
- "Open in Obsidian" button to jump to native app
- Configuration UI for API setup and testing

**Technical Implementation:**
- modules/io/obsidian-bridge.js - Core API integration layer
- modules/ui/obsidian-notes-editor.js - Markdown editor UI
- modules/ui/obsidian-config.js - Configuration panel
- OBSIDIAN_INTEGRATION.md - Complete setup/usage guide

**Coordinate Matching:**
- Parses YAML frontmatter for x/y coordinates
- Calculates distance to clicked element
- Supports nested (coordinates.x) and flat (x:) formats
- Handles missing FMG IDs (common with PostgreSQL imports)

**User Workflow:**
1. Configure Obsidian REST API connection
2. Click burg/marker in FMG
3. System finds matching notes by coordinates
4. Select note or create new one
5. Edit in modern Markdown editor
6. Save syncs to Obsidian vault instantly

This replaces the "Win95-style TinyMCE" editor with a clean,
modern Markdown experience while maintaining compatibility with
the eventual PostgreSQL backend migration. Users can edit notes
in either FMG or Obsidian - both stay in sync via file system.

Version: 1.108.13

modules/ui/obsidian-config.js

@@ -0,0 +1,73 @@
+"use strict";
+
+// Obsidian Configuration UI
+
+function openObsidianConfig() {
+  // Load current config
+  const {apiUrl, apiKey, vaultName, enabled} = ObsidianBridge.config;
+
+  byId("obsidianApiUrl").value = apiUrl || "http://127.0.0.1:27123";
+  byId("obsidianApiKey").value = apiKey || "";
+  byId("obsidianVaultName").value = vaultName || "";
+
+  updateObsidianStatus(enabled);
+
+  $("#obsidianConfig").dialog({
+    title: "Obsidian Vault Configuration",
+    width: "600px",
+    position: {my: "center", at: "center", of: "svg"}
+  });
+}
+
+function updateObsidianStatus(enabled) {
+  const statusEl = byId("obsidianStatus");
+  if (enabled) {
+    statusEl.textContent = "✅ Connected";
+    statusEl.style.color = "#2ecc71";
+  } else {
+    statusEl.textContent = "❌ Not connected";
+    statusEl.style.color = "#e74c3c";
+  }
+}
+
+async function testObsidianConnection() {
+  const apiUrl = byId("obsidianApiUrl").value.trim();
+  const apiKey = byId("obsidianApiKey").value.trim();
+
+  if (!apiUrl || !apiKey) {
+    tip("Please enter both API URL and API Key", false, "error", 3000);
+    return;
+  }
+
+  // Temporarily set config for testing
+  Object.assign(ObsidianBridge.config, {apiUrl, apiKey});
+
+  byId("obsidianStatus").textContent = "Testing connection...";
+  byId("obsidianStatus").style.color = "#f39c12";
+
+  try {
+    await ObsidianBridge.testConnection();
+    updateObsidianStatus(true);
+    tip("Successfully connected to Obsidian!", true, "success", 3000);
+  } catch (error) {
+    updateObsidianStatus(false);
+    tip("Connection failed: " + error.message, true, "error", 5000);
+  }
+}
+
+function saveObsidianConfig() {
+  const apiUrl = byId("obsidianApiUrl").value.trim();
+  const apiKey = byId("obsidianApiKey").value.trim();
+  const vaultName = byId("obsidianVaultName").value.trim();
+
+  if (!apiUrl || !apiKey) {
+    tip("Please enter both API URL and API Key", false, "error", 3000);
+    return;
+  }
+
+  Object.assign(ObsidianBridge.config, {apiUrl, apiKey, vaultName});
+  ObsidianBridge.saveConfig();
+
+  $("#obsidianConfig").dialog("close");
+  tip("Obsidian configuration saved", true, "success", 2000);
+}