Prepare SQLX v0.1.9 release

[openai0229]

What

Release preparation for 0.1.9, which ships sqlx mcp and the four harness integrations merged in #22.

• Version 0.1.8 → 0.1.9 in Cargo.toml ([workspace.package], inherited by every crate), Cargo.lock, java/jdbc/pom.xml, packages/npm-installer/package.json, the --version defaults of scripts/package.py, scripts/package-shared.py and scripts/manifest.py, and the integrations' own manifests under integrations/.
• .github/workflows/packages.yml: all eight v0.1.8 references become v0.1.9, including the release title SQLX 0.1.9 and the npm job's GITHUB_REF_NAME guard.
• scripts/jdbc-fixture.sh and the README build-from-source commands point at sqlx-jdbc-0.1.9.jar.
• Skill declarations move to >=0.1.9, <0.2.0 (skills/sqlx/SKILL.md, references/install-cli.md, references/local-ui.md); the integration README and the Claude plugin description now require CLI 0.1.9+.
• tests/updates.py: CURRENT becomes 0.1.9 and NEXT becomes 0.1.10, so the fake update feed still advertises a newer version.
• docs/release-notes.md rewritten for 0.1.9: the MCP server and its tool set, the authorization annotations, and the four harness integrations.

Verification

$ cargo +stable fmt --all -- --check                      # passed
$ cargo +stable clippy --workspace --all-targets --locked -- -D warnings   # passed
$ cargo +stable test -p ottermind-sqlx --locked           # passed
$ actionlint .github/workflows/*.yml                      # passed
$ python3 -m py_compile scripts/*.py tests/updates.py     # passed
$ python3 tests/distribution.py (skill contract)          # passed

git grep 0.1.8 now only matches the intentional Full Changelog link in the release notes.

Risks and limits

• Nothing is published by this pull request. After it merges, the release needs an annotated v0.1.9 tag on the merge commit and gh workflow run packages.yml --ref v0.1.9 -f publish=true.
• The plugins distribution branch is rebuilt by the workflow added in Generate the plugin distribution branch from CI #23 once that lands; until then it still carries the hand-built copy stamped with 0.1.8.
• The local page plugin is unchanged and keeps its 0.1.4 requirement, so ui-default-0.1.4.zip remains the plugin asset.