Issue 10 - viewer interaction & authoring (follow-up to Issue 9)

[ReCanova]

Description
Next round of viewer work after Issue 9. Focus is on interaction and
authoring: clearer click feedback, neighborhood perimeters, aligning the
Talea (ENVI-met) colours, terrain elevation, richer tree data, and giving
the user tools to add their own features (vegetation, street furniture,
point/line geometry). Plus weather, a print/screenshot button and social
sharing.

Two fixes already landed while opening this issue:

• ENVI-met overlays were flipped vertically (south-up grid georeferenced
  with a north-up affine). Corrected in build_envimet_overlays.py.
• Static export now built into docs/ for GitHub Pages (folder source).

Tasks

Interaction / UI

• Change the click marker icon — the current one is hard to read.
• When a neighborhood is selected, also show its perimeter. If we don't
  want it always on, flash it for a few seconds after selection.
• Screenshot / print button.
  • Let the user choose whether the legend is included in the print.
• Share button for Instagram / social.

Microclimate (Talea / ENVI-met)

• Align the colour scales across the Talea overlays (consistent ramps
  and ranges so layers are comparable).

Terrain

• Handle terrain elevation. Pick the approach:
  • DTM–DSM, at least within the Talea square.
  • Elevation grid via 3D Tiles (quote / heights).

Vegetation

• Split trees into categories (evergreen vs deciduous).
  • Allow inspecting a single tree on click (popup with its attributes).

Authoring / editing

• Let the user add vegetation and street furniture to the scene.
• Evaluate point / line geometry editing so the user can add features.

Data

• Add weather (meteo).

Deliverables
10_viewer-interaction-and-tools.md