feat(progress): remove visual progress bars and iteration counters from messages

[aaight]

Summary

Removes the [██░░░░░░░░] ASCII progress bars and 16% (iteration 11/70) counters from user-facing progress messages posted to Trello/JIRA cards and GitHub PR comments.

• Deleted createProgressBar() helper function from src/config/statusUpdateConfig.ts
• Simplified formatStatusMessage(agentType) — removed iteration and maxIterations params; no longer renders progress bar line
• Simplified formatGitHubProgressComment(headerMessage, agentType) — removed iteration and maxIterations params; removed **Progress:** bar line; simplified footer from <sub>Last updated: iteration N · type</sub> to <sub>type</sub>
• Updated GitHubProgressPoster.update() signature to match (removed iteration/maxIterations params)
• Updated ProgressMonitor fallback call and GitHub poster call to use new signatures
• Removed misleading "Do not include a progress bar — the system adds that separately." instruction from PROGRESS_SYSTEM_PROMPT in progressModel.ts
• Updated all related tests

Test plan

• tests/unit/config/statusUpdateConfig.test.ts — updated to assert no progress bars or iteration counters appear; removed the entire progress bar rendering describe block
• tests/unit/backends/githubPoster.test.ts — updated call signatures (removed iteration/maxIterations args)
• tests/unit/backends/progress.test.ts — no changes needed (mock assertions used toHaveBeenCalled() without checking args)
• Full unit test suite: 3280 tests, all passing
• TypeScript type check: zero errors
• Biome lint: zero errors

Card: https://trello.com/c/699f45849b11747c65f86a7d

🤖 Generated with Claude Code

[nhopeatall]

✨ On it — checking the feat/remove-progress-bar-from-messages branch

[nhopeatall]

LGTM — Clean removal of progress bars and iteration counters from user-facing messages. All call sites updated consistently, createProgressBar helper properly removed, tests updated with both positive assertions (agent label present) and negative assertions (no progress bar/iteration patterns). The ProgressContext.iteration/maxIterations fields are correctly preserved since they still serve the LLM prompt context in progressModel.ts.