Trim whitespace from pending publisher project names

[YS-OH-CORE]

Strip surrounding whitespace from project_name before validating pending
Trusted Publisher forms, matching the existing workflow filename filter. A
pasted name such as example-name is accepted as example-name for all four
providers. Blank or internally spaced names are still rejected, and existing,
prohibited, similar, and standard-library project-name checks remain in place.

Fixes #20587.

The regressions exercise the real project-name service and PostgreSQL database,
including owner-only links for existing projects. Account publisher-management tests also
verify that each provider stores the trimmed name and uses it in the success
message and event. The translation catalog changes only update source locations.

Validation on Ubuntu 24.04 WSL2, Python 3.14.7, PostgreSQL 16.15, with the
repository's pinned test dependencies:

• Original form suite: 125 passed.
• Final regression tests against the original production code: 40 expected
  failures, 20 passing controls, no errors.
• Forms and account/organization publisher-management tests after the fix:
  241 passed.
• Changed common form module and new regression module: 100% statement/branch
  coverage. Ruff, ast-grep, and scoped mypy checks passed.

PostgreSQL 17.5 / the upstream Docker environment and the complete Warehouse
suite were not run. External account lookups are mocked; no live PyPI account
or publisher was changed.

Prepared with OpenAI Codex assistance for Youngseok Oh.