119 improvements to initial form

[pooleycodes]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Description

List of form improvements that have been requested after initial use, can be seen in ticket, key tech changes:

Process locking (ServiceLock)

• New ServiceLock SQLAlchemy model (migration included) stores a lock record keyed by process name, with the locking user's GitHub username and timestamp

Check results — override button

• Users in config/allowed-users.md can override blocking check failures ("columns not found") and proceed to add data anyway

GitHub branch selection — shared macro

• Extracted into datamanager/components/github-branch.html as a reusable Jinja macro consumed by both dashboard_add.html and add-data.html

Add data form improvements

• Start date no longer defaults to today on either form page; it is optional on the first page and required on the second
• Geom type (Point/Polygon) radio group added to the first page, visible only when the tree dataset is selected; defaults to Point
• When geom_type is polygon, {"WKT": "geometry"} is automatically added to the column_mapping in the check_url params and flows through to add_data
• CSV file upload button added alongside "Import from CSV"; selecting a file auto-submits the multipart form to the existing import handler

Dataset list source

• dataset.py now derives the dataset list from PROVISION_CSV_URL (the specification provision CSV) rather than the planning API, ensuring only provisioned datasets appear in the autocomplete
• Display name and collection ID are still completed from the planning API for any matched dataset.

Related Tickets & Documents

• Ticket Link Improvements to initial form #119

QA Instructions, Screenshots, Recordings

Please replace this line with instructions on how to test your changes, a note
on the devices and browsers this has been tested on, as well as any relevant
images for UI changes.

Try upload a csv file, with tree dataset, and override if missing columns

Added/updated tests?

We encourage you to keep the code coverage percentage at 80% and above. Please refer to the Digital Land Testing Guidance for more information.

• Yes - Increase form and organisation tests.
• No, and this is why: please replace this line with details on why tests
  have not been included
• I need help with writing tests