Various Bug Fixes (Undo, Pool Auto-Purge)

[wallstop]

Description

This PR delivers a set of focused quality and reliability updates across editor tools, runtime pooling performance, and project automation.

Key user-facing improvements:

• Fixes multiple Unity editor drawer and dropdown issues (including Linux dropdown rendering, undo reliability, invalid value handling, and multi-object editing behavior).
• Fixes pool auto-purge edge cases and removes major pool usage-tracking overhead, improving performance and correctness under load.
• Fixes metadata/cache path consistency and related editor workflow reliability issues.
• Includes coverage updates across editor/runtime tests and performance docs.

Project quality improvements:

• Adds/updates CI workflows and validation scripts for lint error-code consistency and PowerShell invocation safety.
• Strengthens git hooks and helper scripts used by contributor workflows.
• Updates LLM/agent guidance files to match current automation and validation expectations.

Related Issue

Fixes #

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactor (code change that neither fixes a bug nor adds a feature)

Checklist

• I have added tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have updated the CHANGELOG
• My changes do not introduce breaking changes, or breaking changes are documented

[Copilot]

Pull request overview

This PR tightens reliability across Unity editor tooling (Undo safety), runtime pooling (auto-purge correctness/perf), and contributor automation (new validators, hook hardening, and changed-file preflight) to prevent regressions from slipping through hooks/CI.

Changes:

• Adds a lint-error-code ↔ cspell contract validator (plus CI workflow + regression tests) to ensure new ^[A-Z]{2,}\d{3}$ code families don’t break spelling checks.
• Introduces/expands contributor automation: agent-preflight (changed-file validation + safe fixes), hook hardening (pre-merge-commit delegation, staging retry diagnostics), and new lint/test coverage around PowerShell invocation safety and git-staging helpers.
• Fixes pooling auto-purge throttle edge cases (capacity enforcement + timestamp max-semantics) and improves editor Undo behavior + corresponding tests/docs/perf snapshots.

Reviewed changes

Copilot reviewed 78 out of 78 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
scripts/validate-lint-error-codes.ps1.meta	Adds Unity .meta for new validator script.
scripts/validate-lint-error-codes.ps1	New contract validator to ensure lint-error-code prefixes roundtrip through cspell.
scripts/validate-hook-sync-calls.ps1	Adds validation that pre-merge-commit delegates to pre-commit.
scripts/validate-devcontainer-urls.sh	Adds --contracts-only, absolute Dockerfile support, and contract to reject apt-based PowerShell install.
scripts/tests/test-validate-lint-error-codes.ps1.meta	Adds Unity .meta for new validator test.
scripts/tests/test-validate-lint-error-codes.ps1	New test suite for lint-error-code validator behavior + fixtures.
scripts/tests/test-validate-devcontainer-urls.sh	Extends contracts to cover new apt-PowerShell rejection logic.
scripts/tests/test-sync-script-contracts.ps1	Adds agent/pre-push spelling contract checks.
scripts/tests/test-precommit-integration.sh.meta	Adds Unity .meta for new integration test script.
scripts/tests/test-lint-skill-sizes.ps1	Extends test harness to pass additional args; adds new scoped/critical-mode tests.
scripts/tests/test-lint-pwsh-invocations.ps1.meta	Adds Unity .meta for new PowerShell invocation lint tests.
scripts/tests/test-lint-dependabot.ps1	Updates test invocation to use pwsh -File ... -Paths (production-equivalent).
scripts/tests/test-git-staging-helpers.sh.meta	Adds Unity .meta for new git staging helper regression tests.
scripts/tests/test-git-staging-helpers.sh	Adds regression tests for stderr preservation and trap leakage behavior.
scripts/tests/test-agent-preflight.ps1.meta	Adds Unity .meta for new agent-preflight tests.
scripts/tests/test-agent-preflight.ps1	Adds synthetic-repo tests for agent-preflight (meta/spelling/lock contention).
scripts/lint-skill-sizes.ps1	Adds -Paths scoping + -FailOnCritical behavior and context-check gating.
scripts/lint-pwsh-invocations.ps1.meta	Adds Unity .meta for new PowerShell invocation linter.
scripts/lint-dependabot.ps1	Adds -Paths + remaining-args binding pattern; improves LiteralPath usage and multi-path handling.
scripts/install-hooks.sh	Ensures pre-merge-commit hook exists and is made executable.
scripts/install-hooks.ps1	Adds status/install checks for pre-merge-commit hook.
scripts/git-staging-helpers.sh	Fixes cleanup to avoid persistent stderr redirection; explicit cleanup calls.
scripts/git-staging-helpers.ps1	Adds env-tunable lock retry knobs + safer jitter calculation.
scripts/agent-preflight.ps1.meta	Adds Unity .meta for new agent-preflight script.
scripts/agent-preflight.ps1	New changed-file preflight validator (meta coverage, spelling on changed markdown, etc.).
package.json	Adds agent/preflight scripts and wires new validators/tests into validation pipelines.
docs/performance/relational-components-performance.md	Updates benchmark snapshot table/date.
docs/performance/random-performance.md	Updates benchmark snapshot values and references.
docs/performance/ilist-sorting-performance.md	Updates benchmark snapshot table/date.
cspell.json	Adds new project words/prefixes (e.g., PWS) used by new lint/skills.
Tests/Runtime/Utils/BuffersTests.cs	Ensures PoolPurgeSettings reset for test isolation.
Tests/Runtime/Pool/TypeAwarePoliciesTests.cs	Disables MemoryPressureMonitor for determinism; restores state in teardown.
Tests/Runtime/Pool/PoolSizeAwarePoliciesTests.cs	Disables MemoryPressureMonitor for determinism; restores state in teardown.
Tests/Runtime/Pool/PoolPurgeStrategyTests.cs	Tightens hysteresis/retain tests; clarifies intent; adjusts parameters for determinism.
Tests/Runtime/Pool/PoolAccessFrequencyTests.cs	Adds PoolPurgeSettings resets in multiple fixtures for isolation.
Tests/Runtime/Pool/GradualPurgingTests.cs	Disables/restores MemoryPressureMonitor for determinism.
Tests/Runtime/Pool/GlobalPoolRegistryTests.cs	Adds PoolPurgeSettings reset and MemoryPressureMonitor save/restore.
Tests/Runtime/Performance/PoolPurgeTriggerPerformanceTests.cs	Clarifies performance test intent around throttle fast path.
Tests/Editor/Sprites/TextureSettings/TextureSettingsApplierAPITests.cs	Adds Undo regression test for texture settings application.
Runtime/Utils/Buffers.cs	Fixes auto-purge throttle correctness (capacity bypass) + timestamp advancement semantics.
Editor/Tags/AttributeMetadataCacheEditor.cs	Makes cache purge undoable and ensures asset dirtied/saved.
Editor/Sprites/TextureSettingsApplierAPI.cs	Adds Undo recording on importer mutations (single-record pattern).
Editor/Sprites/SpriteSettingsApplierAPI.cs	Adds Undo recording on importer/settings mutations (single-record pattern).
Editor/Sprites/SpritePivotAdjuster.cs	Records Undo before importer setting mutation.
Editor/Sprites/SpriteCropper.cs	Switches to ApplyModifiedProperties (Undo-aware) and correct modified flags.
Editor/Sprites/ScriptableSpriteAtlasEditor.cs	Adds Undo recording for importer/platform setting mutation batch.
Editor/FitTextureSizeWindow.cs	Records Undo before changing importer max texture size.
Editor/CustomEditors/PolygonCollider2DOptimizerEditor.cs	Records Undo and sets dirty on affected objects.
Editor/CustomEditors/MatchColliderToSpriteEditor.cs	Records Undo and sets dirty on component/collider.
CHANGELOG.md	Documents pooling throttle fix + performance improvements + editor drawer fixes.
.llm/skills/validate-before-commit.md	Updates guidance to require agent preflight before completion; updates validation steps.
.llm/skills/manage-skills.md	Adds agent-preflight to skill maintenance workflow.
.llm/skills/linter-reference.md	Documents new lint/contract scripts and policy for lint-error-code prefixes.
.llm/skills/investigate-test-failures.md	Adds guidance on virtual-clock throttles and pool fixture hygiene.
.llm/skills/git-hook-syntax-portability.md	Documents pwsh -File -- caveat and points to bash→pwsh invocation skill.
.llm/skills/formatting-and-linting.md	Updates hook behavior docs (spelling patch, pre-merge-commit delegation).
.llm/skills/editor-undo-complete.md	New skill documenting undo tier policy and required patterns.
.llm/skills/create-unity-meta.md	Adds agent-preflight step to meta creation checklist.
.llm/skills/bash-pwsh-invocation.md.meta	Adds Unity .meta for new skill doc.
.llm/skills/bash-pwsh-invocation.md	New skill defining safe bash→PowerShell -File invocation rules + enforcement.
.llm/context.md	Regenerates skills index and updates repo rules around preflight and undo policy.
.github/workflows/validate-hooks.yml	Adds precommit integration smoke test step and pwsh availability precondition.
.github/workflows/validate-devcontainer.yml	Adds live URL validation step in devcontainer workflow.
.github/workflows/pwsh-invocations-lint.yml.meta	Adds Unity .meta for new workflow file.
.github/workflows/pwsh-invocations-lint.yml	New workflow to run PowerShell invocation lint + tests.
.github/workflows/lint-error-codes.yml	New workflow to enforce lint-error-code ↔ cspell contract in CI.
.github/ISSUE_TEMPLATE/feature_request.yml	Adds 1.0.1 to version list.
.github/ISSUE_TEMPLATE/bug_report.yml	Adds 1.0.1 to version list.
.githooks/pre-push	Adds lint-error-code contract conditional runs + improved spelling diagnostics/patch output.
.githooks/pre-merge-commit	New hook delegating merge commits to pre-commit to close validation gap.
.githooks/pre-commit	Improves hook robustness (pipefail, staging diagnostics, safe pwsh invocation patterns, scoped lint-skill-sizes, better cspell capture/patch).

[Copilot]

The fallback path for making npx --no-install cspell work in the fixture is internally inconsistent: the comment says it will fall back to a package.json/NODE_PATH approach when symlinks are forbidden, but the implementation actually does a filesystem copy. Either implement the described NODE_PATH/package.json fallback, or update the comment to match the real behavior so future maintainers don’t assume a lightweight fallback exists.

[Copilot]

When symlink creation fails, the test currently does Copy-Item -Recurse of the repo’s entire node_modules into the fixture. That can be extremely slow and disk-heavy (especially on Windows) and contradicts the intent to keep the fixture small. Consider switching this fallback to a lightweight approach (e.g., set NODE_PATH to the real repo’s node_modules for the validator process, or copy only the minimal cspell-related subtree needed for npx --no-install cspell).