docs: refresh release 2.1 docs

[AjayThorve]

Summary

• refresh root README and changelogs for the 2.1.0 release, including skills, sandbox execution, Agent Skill, data-source registry, API/auth, and profiling docs links
• bump package/docs release metadata plus Compose and Helm image/chart tags to 2.1.0
• update deployment docs and the vendored Helm subchart package used by the parent chart

Validation

• helm template aiq deploy/helm/deployment-k8s -n ns-aiq
• helm lint deploy/helm/helm-charts-k8s/aiq
• helm lint deploy/helm/deployment-k8s
• git diff --check
• python3 -m json.tool docs/source/project.json
• python3 -m json.tool docs/source/versions1.json
• commit pre-commit hooks: ruff, uv-lock, YAML checks, detect-secrets, markdown link check

Not run

• Sphinx docs build; sphinx-build is not installed in the local release worktree environment

[greptile-apps]

Greptile Summary

This PR refreshes all release 2.1.0 documentation and metadata: version strings, image tags, Helm chart versions, Sphinx/project config, changelogs, and new doc-index entries for skills/sandbox and agent-skills pages are all updated consistently. All newly-linked doc pages (integration/agent-skills.md, examples/skills-sandbox/index.md, profiling/index.md) exist on disk.

• Version bumped to 2.1.0 across pyproject.toml, docs/source/conf.py, docs/source/project.json, docs/source/versions1.json, Docker Compose defaults, Helm parent chart, and values.yaml image tags.
• Subchart appVersion updated to 2.1.0 and aiq-0.0.4.tgz regenerated, but chart version stays at 0.0.4 — a pre-existing concern flagged in a prior review comment that remains unresolved.
• docs/source/resources/changelog.md promotes the former "Unreleased" block to a formal v2.1.0 section, but the v2.0.0 entry present in the root CHANGELOG.md was never backfilled into the docs changelog, leaving a visible gap in the released history.

Confidence Score: 5/5

Safe to merge — all changes are documentation and metadata updates with no logic or runtime code modified.

The PR touches only docs, version strings, image tags, and Helm chart metadata. Every newly-linked doc page exists on disk, all version strings are internally consistent, and Docker/Helm artifacts have been updated to match the 2.1.0 release. The only outstanding items are a pre-existing subchart version-string mismatch (already noted in a prior review) and a missing v2.0.0 entry in the docs changelog — neither affects runtime behavior.

docs/source/resources/changelog.md is missing the v2.0.0 release entry; deploy/helm/helm-charts-k8s/aiq/Chart.yaml still carries version 0.0.4 while its packaged content reflects 2.1.0.

Important Files Changed

Filename	Overview
README.md	Adds five new feature bullets for 2.1 (skills/sandbox, agent skill, data-source registry, API/auth, profiling), updates roadmap completion status, and clarifies the sandbox security note
deploy/compose/docker-compose.yaml	Bumps default backend and frontend image tags from 2.0.0 to 2.1.0
deploy/helm/deployment-k8s/Chart.yaml	Bumps parent chart version to 2.1.0 and fixes appVersion from '1.0' to '2.1.0'; subchart dependency still pinned to aiq 0.0.4
deploy/helm/helm-charts-k8s/aiq/Chart.yaml	Updates appVersion from 2.0.0 to 2.1.0 but leaves chart version at 0.0.4, while the packaged aiq-0.0.4.tgz was regenerated with the new content — version string mismatch flagged in a prior review comment
docs/source/resources/changelog.md	Replaces the "Unreleased v2.0.1" section with a formal v2.1.0 release entry; the v2.0.0 release entry present in root CHANGELOG.md is absent here, leaving a jump from v1.1.0 to v2.1.0 in the docs changelog
docs/source/conf.py	Updates Sphinx release metadata from 1.2.1 to 2.1.0
pyproject.toml	Bumps aiq-agent package version from 2.0.0 to 2.1.0
docs/source/index.md	Adds two new navigation entries pointing to skills-sandbox and agent-skills docs pages, both of which exist on disk

_{Reviews (5): Last reviewed commit: "update arch diagram" | Re-trigger Greptile}

[lvojtku]

Added comments and approved.