fix: derive the version from src/__about__.py

[FreezeManny]

Closes #73.

Problem

uv sync --locked fails on every release PR (e.g. #70):

error: The lockfile at `uv.lock` needs to be updated, but `--locked` was provided.

uv records a version for the root package in uv.lock only when pyproject.toml states one statically. release-please bumps pyproject.toml and leaves the lock behind, so the two disagree.

The blast radius is wider than the release PR: Test runs on pull_request, so once a release PR merges, the stale lock lands on main and every subsequent PR fails the same way. Docs (uv sync --locked --group docs, on release: published) would fail on the release itself. Publish is unaffected — it only runs uv build.

Fix

Make the version dynamic. With dynamic = ["version"], uv omits the field from the lock entirely, so a release bump cannot desynchronise it and --locked stays strict for the dependabot PRs it was added for.

root version	after a 0.9.1 → 0.10.0 bump	uv lock --check
static (before)	lock now stale	fails
dynamic (after)	lock unchanged — no version recorded	passes

release-please now updates src/__about__.py through its generic (comment-annotation) updater instead.

Also dropped

The uv.lock entry added to release-please-config.json in #72 was a silent no-op. Its jsonpath is evaluated by jsonpath-plus, which does not apply the [?(@.name=='labops')] filter, so it matched nothing and only logged a warning — visible in the Release Please run for #70:

⚠ No entries modified in $.package[?(@.name=='labops')].version

Non-matching paths only warn, never fail, which is why #72 looked like it worked.

Verification

• uv lock → Updated labops v0.9.1 -> (dynamic); the version field is gone from the lock
• uv sync --locked passes from a clean environment and installs labops==0.9.1
• bumping __about__.py to 0.10.0 leaves uv lock --check passing, and uv build produces labops-0.10.0 artifacts
• 550 tests pass; ruff check clean

Not verifiable locally: that release-please actually rewrites the annotated line — that only proves out on the next Release Please run. It uses the annotation-based generic updater rather than the jsonpath path that failed before.

After merge

release-please regenerates #70 against the new config, bumping src/__about__.py instead of pyproject.toml, and its stale-lock diff disappears.