chore(17-I): regenerate uv.lock for v0.3.0a7

Single-line bump of the supamem self-reference version inside uv.lock
from 0.3.0a6 → 0.3.0a7. Generated by `uv sync --extra dev --extra eval
--extra ast-chunker` against the v0.3.0a7 pyproject.toml. No third-party
dependency version drift.

Release verification done in this commit's lead-up:

  - `uv build` clean (dist/supamem-0.3.0a7-py3-none-any.whl + .tar.gz)
  - `uvx twine check dist/*` PASSED on both artefacts (PEP 639:
    `license = "MIT"` SPDX, no `License ::` classifier)
  - `uv run --no-sync ruff check src tests` clean
  - Regression-lock suite green (71/71):
      tests/test_adr_phase16_floors.py
      tests/test_adr_phase17_uplift.py
      tests/test_runner_byte_identical.py
      tests/test_filters_byte_identical.py
      tests/test_readme_translations_phase16.py
      tests/test_readme_translations_phase17.py
  - Full pytest suite: 997 passed, 6 skipped, 1 pre-existing failure
    (`test_tree_sitter_chunker.py::test_chunk_count_3x_vs_markdown_header`
    — Req-02 ratio asserts 3.0x; measures 2.92x at the fb8e040 anchor;
    same failure reproduces on the 17-B GREEN commit `0801a83`, so this
    is NOT a 17-I regression). Documented in
    `.planning/phases/17-coderag-chunker-and-hyde-uplift/deferred-items.md`.
    Does not block v0.3.0a7 release — `tree_sitter_code` is opt-in via
    `[ast-chunker]` extra; the failing assertion is a private-CI gate,
    not a public-surface contract.

Plan: 17-I (Task 3 of 3 automated). Task 4 (annotated tag + PyPI push)
remains human-only per AGENTS.md — PyPI versions are immutable.

Author: dzmitrys-dev