Upgrade CodeQL caching and dependencies installation

[mbaluda]

This pull request enhances the unit_tests and pack-gen workflows by introducing a persistent cache for compiled queries.

Description

It updates the related GitHub Actions and scripts to support the new caching mechanism.

Performance Improvement

When the cache is fully warm (no query needs to be recompiled), performance is improved by ~90%

Workflow	First run	Latest run	Reduction	Speedup
Unit tests	2h 09m 48s	12m 16s	90.5%	10.6x
Pack generation	1h 57m 54s	10m 25s	91.2%	11.3x

Change request type

• Release or process automation (GitHub workflows, internal scripts)
• Internal documentation
• External documentation
• Query files (.ql, .qll, .qls or unit tests)
• External scripts (analysis report or other code shipped as part of a release)

Rules with added or modified queries

• No rules added
• Queries have been added for the following rules:
  • rule number here
• Queries have been modified for the following rules:
  • rule number here

Release change checklist

A change note (development_handbook.md#change-notes) is required for any pull request which modifies:

• The structure or layout of the release artifacts.
• The evaluation performance (memory, execution time) of an existing query.
• The results of an existing query in any circumstance.

If you are only adding new rule queries, a change note is not required.

Author: Is a change note required?

• Yes
• No

🚨🚨🚨
Reviewer: Confirm that format of shared queries (not the .qll file, the
.ql file that imports it) is valid by running them within VS Code.

• Confirmed

Reviewer: Confirm that either a change note is not required or the change note is required and has been added.

• Confirmed

Query development review checklist

For PRs that add new queries or modify existing queries, the following checklist should be completed by both the author and reviewer:

Author

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

Reviewer

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

[Copilot]

Pull request overview

Adds persistent CodeQL compilation caching to accelerate unit tests and pack generation. A change note is not required because query behavior and release artifacts are unchanged.

Changes:

• Restores and saves versioned compilation caches.
• Shares caches across dependency installation, compilation, testing, and bundling.
• Updates unit-test caching to actions/cache@v6.

Show a summary per file

File	Description
scripts/install-packs.py	Adds common-cache support to pack installation.
.github/actions/install-codeql-packs/action.yml	Exposes the cache directory input.
.github/workflows/codeql_unit_tests.yml	Caches compiled queries for unit tests.
.github/workflows/code-scanning-pack-gen.yml	Caches compilation and bundle generation.

Review details

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• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Balanced