IntelliJ Platform Gradle Plugin's local cache (downloaded IDE artifacts,
update locks, javaagent locks). Regenerated on every Gradle build, no
reason for them to be in the tree.

Adds .intellijPlatform/ to .gitignore and removes the three files that
had slipped in (a self-update.lock, coroutines-javaagent.lock, and a
bundled-module XML descriptor).

Two workflow files under .tangled/workflows/, both running under nixery
with jdk21 / rustc / cargo / git from nixpkgs.

ci.yml fires on every push: builds the Rust oracle binary, runs the
engine test suite (which includes the differential-vs-Helix tests via
OracleClient), then builds the plugin distribution zip. Catches broken
commits before they get tagged.

release.yml fires on tag push: same steps, then attaches the resulting
Helicase-*.zip to the tag via spindle-artifact (third-party tool at
git+https://tangled.org/regnault.dev/spindle-artifact). Under the hood
spindle-artifact authenticates with ATProto via app password, uploads
the zip as a blob, and creates a record pinning the blob to the named
tag — Tangled's actual mechanism for per-tag attachments.

The publishing account's handle (isaaccorbrey.com) is hardcoded in
release.yml's `environment` block; the secret half (ATPROTO_APP_PASSWORD)
lives in repo secrets and Spindle injects it at run time.

One known fragility: `git tag | tac | head -1` fishes "the latest tag"
out of the runner rather than reading the trigger context directly.
That works while CI is fired by the tag actually being latest. If
non-chronological tags ever appear, the upload step picks the wrong
one; worth swapping to a Spindle-exposed variable when one becomes
available.

README at repo root covering features, sideload install (incl. Settings →
Helicase first-run tip), product compatibility table (all JetBrains
IntelliJ-Platform IDEs), and dual-license pointer. Compatibility table
verified for DataGrip; rest marked "needs verification" — plugin only
depends on `com.intellij.modules.platform` so loading should be uniform.

Dual MIT + Apache 2.0 license at repo root (LICENSE-MIT, LICENSE-APACHE)
following the Rust-ecosystem convention. README's "licensed under MIT or
Apache 2.0, at your option" links point at both files.

CHANGELOG.md in Keep-a-Changelog format with custom section names that
read more naturally for an IDE-plugin audience: Release highlights,
Breaking changes, Deprecations, New features, Fixed bugs. Initial
[Unreleased] entry summarizes the 0.1.0 surface — Helix config ingest,
chord intake, dynamic minor modes, gw jump labels, LSP gotos, : command
mode, persistent settings, registers, logger, engine command surface,
and the differential-testing harness.

Plugin build pipeline (plugin/build.gradle.kts):
- `org.jetbrains.changelog` plugin reads CHANGELOG.md and renders the
current version's block (or [Unreleased] fallback) as HTML into the
plugin descriptor's <change-notes>, so the IDE plugin-info dialog
shows the same release notes the repo does.
- Single-source `version = "0.1.0"` at the top drives plugin descriptor
version, changelog plugin version lookup, and distribution zip name.
- `buildPlugin` task's archive base renamed from "plugin" to "Helicase"
so the sideload zip is `Helicase-0.1.0.zip` (matches the README's
install instructions).
- `repositoryUrl = "https://tangled.org/isaaccorbrey.com/helicase"` for
the changelog plugin's auto-linking of references.