Add Pi to databricks aitools install

[lennartkats-db]

Changes

• Register Pi as a skills-only agent (it reads SKILL.md but has no databricks plugin). install/update discover Pi via ~/.pi/agent (honoring PI_CODING_AGENT_DIR) and write Databricks skills into its skills directory, globally and project-scoped (.pi/skills).
• Pi is the first non-plugin agent with project scope, so update --scope project now also picks up agents whose skills live in the project via DetectProjectInstalled (home-based config-dir detection alone misses them).
• Derive the "Supported agents" / skills-only lists in the help text from the registry (SupportedNames/SkillsOnlyNames) so they can't drift as agents are added.
• Add a PI telemetry agent type.

Why

Pi speaks the SKILL.md agent-skills standard, so it can use Databricks skills once they're installed: we just weren't installing for it.

Tests

• Unit tests for Pi's config dir and override (TestPiConfigDir), its global/project skill paths and project detection (TestSkillAgentRegistryPaths, TestDetectProjectInstalled), the registry-derived help (TestSupportedNamesMatchesRegistry, TestSkillsOnlyNamesMatchesRegistry), and update --scope project picking up .pi/skills (TestUpdateProjectIncludesProjectSkillAgents).
• task lint, go build ./..., and the aitools acceptance tests pass.
• Verified end to end against a live model: after databricks aitools install, Pi loads the databricks-core skill in a real session.

[github-actions]

An authorized user can trigger integration tests manually by following the instructions below:

Trigger:
go/deco-tests-run/cli

Inputs:

• PR number: 6198
• Commit SHA: 6e89d7fd31d2a20d43b0b33a7674f735a58adaf6

Checks will be approved automatically on success.

[github-actions]

Approval status: pending

/cmd/aitools/ - needs approval

6 files changed
Suggested: @simonfaltum
Also eligible: @parthban-db, @renaudhartert-db, @fjakobs, @Shridhad, @atilafassina, @keugenek, @igrekun, @pkosiec, @MarioCadenas, @pffigueiredo, @ditadi, @calvarjorge, @hectorcast-db, @tanmay-db, @Divyansh-db, @tejaskochar-db, @mihaimitrea-db, @chrisst, @rauchy

/libs/aitools/ - needs approval

6 files changed
Suggested: @simonfaltum
Also eligible: @parthban-db, @renaudhartert-db, @fjakobs, @Shridhad, @atilafassina, @keugenek, @igrekun, @pkosiec, @MarioCadenas, @pffigueiredo, @ditadi, @calvarjorge, @hectorcast-db, @tanmay-db, @Divyansh-db, @tejaskochar-db, @mihaimitrea-db, @chrisst, @rauchy

/libs/telemetry/ - needs approval

Files: libs/telemetry/protos/aitools_install.go
Suggested: @simonfaltum
Also eligible: @parthban-db, @renaudhartert-db, @hectorcast-db, @tanmay-db, @Divyansh-db, @tejaskochar-db, @mihaimitrea-db, @chrisst, @rauchy

General files (require maintainer)

Files: .nextchanges/cli/aitools-pi.md
Based on git history:

• @simonfaltum -- recent work in cmd/aitools/, libs/aitools/agents/, libs/aitools/installer/

_{Any maintainer (@andrewnester, @anton-107, @denik, @pietern, @shreyas-goenka, @simonfaltum, @renaudhartert-db, @janniklasrose) can approve all areas.
See OWNERS for ownership rules.}

[lennartkats-db]

Closing in favor of #6199; PR should not be on a fork.