fix: make demo-load writable, fix photo strip a11y, fix M7 marker click

- Makefile: add chown 1000:1000 after demo-load so Grav can create entries
- Makefile: add collection config to demo dailies.md (page.collection() needs it)
- base.html.twig: add tabindex="0" to journal-photo-strip for keyboard access (AX1-AX3)
- maps.spec.js: use force:true on M7 marker click (start/end overlap at Campiglia)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Vgmzx8VTTTmCskSpQtsLTr

tests/ui/maps.spec.js

@@ -94,8 +94,8 @@ test('M7: clicking map marker briefly highlights the corresponding entry card',
                !window.tripMap.isRotating();
     }, { timeout: 15000 });
 
-    // Click the first marker
-    await page.locator('.maplibregl-marker').first().click();
+    // Click the first marker (force bypasses overlap when start/end share the same location)
+    await page.locator('.maplibregl-marker').first().click({ force: true });
 
     // Within 500ms of click + delay, one journal-post should have is-highlighted
     await expect(page.locator('.journal-post.is-highlighted')).toBeVisible({ timeout: 1500 });