refactor(server): extract the progression routes into routers/progression.py (R3)

[byrongamatos]

4 progression routes (overview / add-paths / onboarding / events, spec 010) + their exclusive helpers (_goal_ui_progress, the 112-line _progression_overview) + the _PROGRESSION_EVENT_TYPES whitelist.

The two shared server accessors read through the seam: get_progression_content (landed for shop #851) and builtin_diagnostic_filename (new slot — a trivial const-returning fn shared with stats' api_record_stats). Both injected via the second appstate.configure() after their defs (the import-top configure runs before them). The cache + fns stay in server.py, so test_progression_api's server._progression_content patch is untouched — 0 retarget.

Bodies verbatim (@app→@router, meta_db→appstate.meta_db, _clean_str from reqfields). server.py: 7,798 → 7,594.

Verification

• Route table identical (143); both seam accessors wired; pyflakes clean.
• pytest 2401 passed (63 in test_progression_api, whose _progression_content patch still works).
• Boot smoke: GET /api/progression 200 (drives _progression_overview + both accessors); events 400 on bad body. npm run lint 0; Codex 0 findings.

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • Added progression APIs for viewing progression status, selecting paths, managing onboarding, and recording supported progression events.
  • Added detailed progression summaries, including goals, mastery, streaks, challenges, wallet status, and available paths.
  • Added validation for progression events and onboarding actions, with clear errors for invalid requests.

• Documentation

  • Updated progression documentation to reflect the current router count.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

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Configuration used: defaults

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Run ID: d70b8877-cfe3-4564-8817-9fd780d9b0e4

📥 Commits

Reviewing files that changed from the base of the PR and between 5f58af4 and 8f3a191.

📒 Files selected for processing (4)

• docs/size-exemptions.md
• lib/appstate.py
• lib/routers/progression.py
• server.py

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📝 Walkthrough

Walkthrough

The progression API was moved from server.py into lib/routers/progression.py. Application state now exposes builtin_diagnostic_filename, and the server registers the new router with the required dependencies. The server size-exemption documentation was updated accordingly.

Changes

Progression router extraction

Layer / File(s)	Summary
Application-state seam lib/appstate.py	Adds the builtin_diagnostic_filename application-state slot, defaulting to None and accepted by configure().
Progression router implementation lib/routers/progression.py	Defines the progression router and its overview, path selection, onboarding, and validated event endpoints.
Server router wiring server.py, docs/size-exemptions.md	Registers the progression router, supplies its appstate dependencies, removes the inline handlers, and updates the documented router count.

Estimated code review effort: 3 (Moderate) | ~20 minutes

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor/r3-router-progression

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