Add taginfo project file (deflock.org/taginfo.json)

[jeremyknows]

Summary

Adds a taginfo project file
at webapp/public/taginfo.json, served at https://deflock.org/taginfo.json.
It enumerates the OpenStreetMap tags DeFlock reads and writes for ALPR nodes so
the project appears in Taginfo and
the OSM community can see which tags the app relies on.

Addresses #88.

Diff scope

• webapp/public/taginfo.json (new, 17 tags) — static file, served verbatim from the site root.

The tags are taken from the project's own source, not invented:

• Write tags — webapp/src/constants.ts (lprBaseTags): man_made=surveillance,
  surveillance:type=ALPR, surveillance=public, camera:type=fixed,
  surveillance:zone=traffic, plus camera:mount, electricity, note.
• Read/preserved tags — serverless/alpr_cache/src/alpr_cache.py (WHITELISTED_TAGS):
  operator, manufacturer, direction, brand, camera:direction,
  surveillance:brand, surveillance:operator, surveillance:manufacturer,
  wikimedia_commons.

All entries use object_types: ["node"], matching how ALPRs are mapped (the
Overpass query in alpr_cache.py selects node["man_made"="surveillance"]["surveillance:type"="ALPR"]).

Verification

Schema-validated against the official
taginfo-project-schema.json
(ajv + ajv-formats, draft-07):

VALID ✓ — conforms to taginfo project schema
tags: 17 | project fields: name,description,project_url,doc_url,icon_url,contact_name,contact_email

Build confirms the file ships as-is to the site root:

$ bun run build
✓ built in 1.89s
$ ls -l dist/taginfo.json && jq empty dist/taginfo.json
-rw-r--r--  1  3124  dist/taginfo.json
(valid JSON)

What was NOT tested / remaining step

• The file is not yet registered with the taginfo projects list — that is a
  separate one-line PR to taginfo/taginfo-projects
  pointing at https://deflock.org/taginfo.json, which can only be done once this
  URL is live. Happy to open that follow-up once you've deployed, or you can — your call.
• Live serving of the URL was not verified (the file isn't deployed yet); it's a
  static asset in webapp/public/, which Vite copies verbatim to the site root
  (confirmed in the build output above).

Test plan

• Merge + deploy, then load https://deflock.org/taginfo.json and confirm it serves.
• Optionally validate at https://taginfo.openstreetmap.org/ after registration.