chore: release v0.3.2

[Verdenroz]

What changed

• Froze the ## Unreleased heading in CHANGELOG.md to ## 0.3.2 - 2026-09-11 and wrote its Overview and Upgrade notes.
• Bumped [workspace.package] version and the eight [workspace.dependencies] requirements from 0.3.1 to 0.3.2.
• Regenerated Cargo.lock. Only version lines moved; no dependency was added, removed, or changed.
• Bumped the version strings in README.md and soothfast.toml.

Why

0.3.1 gave the action its features and regeneration inputs, so CI could be
told once what a repository needs. A developer running the CLI by hand still
repeated the same flags on every invocation, and two defects surfaced once
adopters started bumping across versions. This release carries all three
fixes: soothfast.toml holds the feature and package defaults, the gate stops
letting a reference it could not pin decide a verdict quietly, and the
changelog drops the bot's own regeneration commits instead of listing the
paperwork as changes.

Everything here is additive and opt-in. A repository on soothfast = "0.3"
picks it up without touching its manifest.

How was this tested

• cargo fmt --all -- --check: clean.
• cargo clippy --workspace --all-targets -- -D warnings: clean.
• cargo test --workspace --no-fail-fast: 817 passed, 4 ignored, 1 failed. The failure is invoke::tests::a_plain_directory_in_the_repo_is_not_a_worktree_root, which asserts the workspace root is not a linked git worktree. It fails from any linked-worktree checkout and passes from a plain one, which is what CI uses. Confirmed by running the same built test binary from both.
• cargo check --workspace after the bump: clean, all ten crates resolve at 0.3.2.
• Read the frozen section against git log v0.3.1..master: it lists feat: read gate and changelog features from soothfast.toml #195, fix: pin the gate harness across an incompatible requirement #196 and fix: drop the soothfast bot's own commits from the changelog #199, and none of the four soothfast-bot regeneration commits. Those exclusions are the filter from fix: drop the soothfast bot's own commits from the changelog #199 running against real history.
• make gate BASE=master was not run. This commit changes no measured code.

Checklist

• make check passes (fmt, clippy -D warnings, cargo test --workspace)
• make gate BASE=master passes, or any intentional cost change is explained above
• Tests added/updated for new behavior (not required for docs/CI-only changes)
• Public API items have /// doc comments
• No new dependency, or its justification is included above (see Dependency Policy)
• Docs (README.md, docs/, soothfast:bind/soothfast:claim markers) updated if behavior changed

[soothfast-bot]

soothfast gate

gate: measuring merge-base of origin/master in worktree (interleaved rounds)
gate: gating backend = callgrind
gate: build=08f03a noise_floor=0.05% thresholds: instructions +5% ir +5% walltime +10.0% alloc/size +5% polls/wakes +5%
ok    soothfast_spec::bench_openapi_diff instructions 41528736.0 -> 41193117.0 (-0.8%)
ok    soothfast_spec::bench_openapi_diff callgrind_ir 41528736.0 -> 41193117.0 (-0.8%)
ok    soothfast_spec::bench_openapi_diff walltime_median_ns 4422841.0 -> 4585473.0 (+3.7%)
ok    soothfast_spec::bench_openapi_diff allocs 77722 -> 77722 (allowed <= 81608)
ok    soothfast_spec::bench_openapi_diff alloc_bytes 10815487 -> 10815487 (allowed <= 11356261)
ok    soothfast_spec::bench_openapi_document instructions 16803544.0 -> 16801872.0 (-0.0%)
ok    soothfast_spec::bench_openapi_document callgrind_ir 16803544.0 -> 16801872.0 (-0.0%)
ok    soothfast_spec::bench_openapi_document walltime_median_ns 1578469.0 -> 1566992.0 (-0.7%)
ok    soothfast_spec::bench_openapi_document allocs 30152 -> 30152 (allowed <= 31659)
ok    soothfast_spec::bench_openapi_document alloc_bytes 4715065 -> 4715065 (allowed <= 4950818)
ok    soothfast_spec::bench_serialize_yaml instructions 61226129.0 -> 61625912.0 (+0.7%)
ok    soothfast_spec::bench_serialize_yaml callgrind_ir 61226129.0 -> 61625912.0 (+0.7%)
ok    soothfast_spec::bench_serialize_yaml walltime_median_ns 5494625.0 -> 5467726.0 (-0.5%)
ok    soothfast_spec::bench_serialize_yaml allocs 74277 -> 74277 (allowed <= 77990)
ok    soothfast_spec::bench_serialize_yaml alloc_bytes 8533615 -> 8533615 (allowed <= 8960295)
ok    soothfast_spec::bench_openapi_diff assert complexity: claimed O(n); growth drift x1.55 over sizes [16, 64, 256] (limit x2.5)
ok    soothfast_spec::bench_openapi_document assert complexity: claimed O(n); growth drift x1.57 over sizes [16, 64, 256] (limit x2.5)
ok    soothfast_spec::bench_serialize_yaml assert complexity: claimed O(n); growth drift x1.25 over sizes [16, 64, 256] (limit x2.5)
gate: passed (3 item(s))