feat: add lane configuration model and defaults

[itsmiso-ai]

Fixes #382

Summary

Add a central lane config helper module (src/lib/lane-config.ts) so all lane consumers go through one helper instead of scattered string unions and constants.

Changes

• LaneConfig interface with id, title, claimable, description?, color?, defaultAgent?
• Default config: normal (claimable), escalated (claimable), backlog (non-claimable) — equivalent to current behavior
• Public helpers:
  • getConfiguredLanes() — all configured lanes
  • getClaimableLanes() — only claimable lanes
  • isValidLane(id) — is the lane id configured?
  • isClaimableLane(id) — is the lane id configured and claimable?
  • getBacklogLane() — the non-claimable fallback lane
  • getLaneById(id) — look up a lane by id
  • getLaneIds() — all configured lane ids
• Validation: unique ids, non-empty id/title, at least one claimable lane
• Runtime overrides: setLaneConfig() / resetLaneConfig() for custom configs
• 17 unit tests covering defaults, custom config, and validation edge cases

Compatibility

Existing installs behave exactly the same when no custom config is provided. No database migration required.

[its-saffron]

AI Automated Review

Full PR review.

Analysis engine: review@https://litellm.jory.dev/v1 (openai) — fast route

Summary

This PR introduces a centralized lane configuration module (src/lib/lane-config.ts) to replace scattered string unions and constants. This allows for a more robust and configurable way to manage execution lanes (Normal, Escalated, Backlog) across the application.

Change-by-change findings

src/lib/lane-config.ts

• Implementation: Correctly implements the LaneConfig and LaneConfigSet interfaces as requested in PR 382.
• Defaults: Provides the required default configuration (Normal, Escalated, Backlog) with appropriate claimable settings.
• Validation: The validateLaneConfigSet function robustly checks for non-empty IDs, unique IDs, non-empty titles, and ensures at least one lane is claimable.
• Encapsulation: Uses a private laneConfigSet and provides a deep copy via getConfiguredLanes() to prevent accidental mutation of the internal state.

src/lib/lane-config.test.ts

• Coverage: Comprehensive unit tests covering default configuration, custom configuration, validation error cases (empty array, duplicate IDs, empty IDs, missing titles, all non-claimable), and the resetLaneConfig functionality.
• Mutation Testing: Includes a test case to verify that getConfiguredLanes() returns a copy and does not allow direct mutation of the internal state.

Linked Issue Fit

• Requirement Match: The implementation perfectly aligns with the requirements and proposed config shape in PR 382.
• Acceptance Criteria:
  • Current default lanes are available through the new config helper.
  • A single claimable lane plus backlog can be represented.
  • Multiple claimable lanes plus backlog can be represented.
  • Invalid lane IDs are rejected or ignored with a clear error.
  • Unit tests cover default config and at least one custom config.
• Compatibility: As stated in the PR, existing installs will behave identically as the defaults match the previous hardcoded behavior.

Standards Compliance

• Code Standards: Follows repository conventions for error handling (throw new Error) and validation.
• Testing: Uses vitest and provides high coverage for the new logic.
• Secrets: No secrets are committed.