Task/otel project connection

[muzamilkm]

Summary

Adds DevLake project placement for Claude Code OTel connections so a team credential can be associated with one or more DevLake projects without treating project membership as telemetry attribution.

Project placement is stored as DevLake configuration metadata. The trusted devlake_team label still comes from the authenticated OTel credential, while project-scoped dashboards resolve the projects linked to those teams through MySQL.

Included

• Adds _tool_claude_code_otel_connection_projects and migration support for many-to-many OTel connection/project placement.
• Requires at least one existing DevLake project when creating or updating an OTel connection.
• Adds APIs to list available projects, list a project's OTel connections, replace connection placements, validate project removal, and clean up project placements.
• Adds project selection to the OTel connection create/edit flow and shows linked projects in the OTel management UI.
• Adds a Claude Code OTel panel to project details with project-scoped connection visibility and a shortcut to create a connection for that project.
• Adds project and OTel-team variables to the Claude Adoption Grafana dashboard. Prometheus panels filter by trusted devlake_team, while MySQL maps the selected DevLake project to its linked teams.
• Explicitly removes any client-provided devlake_project attribute in the Collector. Project placement is not repository-level attribution and is never trusted from telemetry.
• Prevents deleting the final project placement of an active OTel connection through the normal Config UI project-deletion flow. The connection must be revoked or placed in another project first.

Project Lifecycle Boundary

The normal Config UI delete flow performs OTel preflight and placement cleanup before deleting a project.

A direct client of the generic DELETE /projects/:projectName API can still bypass this plugin-owned lifecycle because upstream DevLake currently exposes no project-deletion extension hook. This can leave stale OTel placement metadata after direct API deletion.

Fixing that cleanly requires an upstream/core project lifecycle hook and is intentionally left outside this PR to avoid coupling the OTel feature directly into core deletion logic. Issue created: apache#9081

Scope and Upstream Coupling

Most backend changes remain isolated in backend/plugins/claude_otel, with Config UI integration limited to the existing OTel screens and project detail/delete flows.

The Grafana change only adds project/team filtering to the Claude dashboard. Metric attribution continues to use the trusted credential-derived devlake_team label rather than introducing a project label into telemetry.

Verification

This PR includes focused coverage for:

• OTel project placement validation and replacement
• final-active-placement deletion protection
• project/OTel UI helpers
• Claude dashboard project/team query wiring

Additional staging validation will cover creating shared-team placements, project-scoped dashboard filtering, moving a connection between projects, and project deletion behavior.

Deferred

• Repository-level or per-event project attribution. OTel project placement is governance/display metadata only and must not be inferred as source-code attribution.
• Any broader project-aware telemetry model beyond team-to-project placement.