refactor: remove unused exported functions from core modules

[aaight]

Summary

Removes dead exports from 6 source files to reduce the public API surface to match actual usage patterns.

• src/github/client.ts: Removed getAuthenticatedUser() standalone function, addIssueCommentReaction(), addReviewCommentReaction(), branchExists() methods, and GitHubReactionContent type (none were called outside this file)
• src/trello/client.ts: Removed export keyword from getTrelloCredentials() — function kept for internal use by getClient() and trelloFetch()
• src/trello/types.ts: Removed dead re-export line for TrelloCard, TrelloComment, TrelloAttachment; TrelloCredentials interface retained
• src/pm/lifecycle.ts: Removed export keyword from extractPRTitle() — function kept for internal use by handleSuccess()
• src/config/env.ts: Removed loadEnvConfig() and its getEnvOrThrow() helper; loadEnvConfigSafe() and getEnvOrDefault() preserved
• src/triggers/shared/backlog-check.ts: Removed deprecated isBacklogEmpty() function (marked @deprecated, zero external callers); isPipelineAtCapacity() unaffected

Test files updated:

• tests/unit/github/client.test.ts: Removed branchExists, addIssueCommentReaction, addReviewCommentReaction, getAuthenticatedUser describe blocks and mock entries
• tests/helpers/sharedMocks.ts: Removed addIssueCommentReaction, addReviewCommentReaction, branchExists from mockGithubClient
• tests/unit/pm/lifecycle.test.ts: Removed extractPRTitle import and describe block
• tests/unit/trello/client.test.ts: Removed getTrelloCredentials import and describe block
• tests/unit/triggers/shared/backlog-check.test.ts: Removed entire isBacklogEmpty describe block

Test plan

• npm run typecheck passes (zero errors)
• npm run lint passes (zero errors)
• npm test passes (293 test files, 5438 tests)

Closes: https://trello.com/c/69b8361eabcecdb304177206

🤖 Generated with Claude Code

🕵️ claude-code · claude-sonnet-4-6 · run details

[nhopeatall]

LGTM — Clean dead-code removal. I verified every deleted export has zero external callers in src/:

• getAuthenticatedUser(), addIssueCommentReaction(), addReviewCommentReaction(), branchExists(), GitHubReactionContent — no references outside src/github/client.ts
• loadEnvConfig() / getEnvOrThrow() — zero callers anywhere
• isBacklogEmpty() — zero callers, correctly deprecated
• extractPRTitle() — only called within src/pm/lifecycle.ts (correctly made module-private)
• getTrelloCredentials() — only called within src/trello/client.ts (correctly made module-private)
• TrelloCard, TrelloComment, TrelloAttachment re-exports from trello/types.ts — no consumers import these types from types.ts; they import from trello/client.ts directly

Test updates are consistent with the source changes — removed test blocks correspond exactly to removed/unexported functions. The satisfies GitHubClientContract on mockGithubClient in sharedMocks.ts ensures the mock stays in sync with the real client shape, so the removal of mock methods is type-safe. All CI checks pass.

🕵️ claude-code · claude-opus-4-6 · run details