chore(changelog): document v0.2.0 [Unreleased] notes on develop

[leostar0412]

Summary

Updates CHANGELOG.md under [Unreleased] to reflect work already merged into develop since 0.1.0, in preparation for a v0.2.0 release. No application code changes.
Notable additions captured: reddit_activity_tracker, collector TrackerResult / lifecycle hooks, protocol DTO serialization, core.adapters, API contract tests, Pyright coverage for cppa_user_tracker and cppa_pinecone_sync.
Notable changes captured: discord_activity_tracker per-channel incremental export and backfill failure reporting, slack_event_handler Chrome-profile token extraction, identity-hub decoupling in boost_mailing_list_tracker, concurrency refactor, import-linter and service-layer write enforcement, Pydantic boundary schemas, CI/deploy workflow updates.
Also adds Removed, Fixed, Security, and Documentation sections (deprecated collector base classes, Slack job-queue locking fix, pip-audit/CVE bumps, tutorial/ADR/architecture docs).

Apps touched

• (documentation only — CHANGELOG.md)
• Release notes cover: reddit_activity_tracker, core, discord_activity_tracker, slack_event_handler, boost_mailing_list_tracker, github_activity_tracker, boost_library_tracker, cppa_user_tracker, cppa_pinecone_sync, CI/workflows

Test plan

• python -m pytest (or scoped: python -m pytest <app>/tests) — N/A (no code changes)
• uv run pyright (if typed code changed) — N/A
• lint-imports (if imports or cross-app coupling changed) — N/A
• App command smoke-tested (if collector/command changed): — N/A
• Reviewed CHANGELOG.md [Unreleased] entries against recent merges on develop

Docs / coupling

• cross-app-dependencies.md updated (if FKs or cross-app imports changed) — N/A
• python scripts/generate_service_docs.py run (if services.py or core/protocols.py changed) — N/A
• App README or docs/ updated (if behavior or ops changed) — changelog only; linked docs referenced in release notes

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Closes #276

Summary by CodeRabbit

• New Features

  • Reddit activity tracking capability
  • Enhanced collection framework with improved lifecycle management
  • Protocol serialization support

• Changed

  • Updated Discord and Slack integration behaviors
  • Improved error handling and validation mapping
  • Enhanced concurrency and scheduling improvements

• Bug Fixes

  • Resolved Slack job queue synchronization issue

• Documentation

  • Expanded tutorial and architecture guides
  • Added architecture decision records

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5cf6c7ba-5126-4ba9-a89a-89aa3ec5ad75

📥 Commits

Reviewing files that changed from the base of the PR and between 884ef63 and 3f8f478.

📒 Files selected for processing (1)

• CHANGELOG.md

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📝 Walkthrough

Walkthrough

This PR updates CHANGELOG.md to document the v0.2.0 release. The Unreleased section is reorganized and expanded across Added, Changed, Removed, Fixed, Security, and Documentation subsections to capture new features (Reddit activity tracker, updated collector contract, protocol serialization, stable adapters), behavioral changes (Discord/Slack improvements, concurrency refactor), deprecated classes, a bug fix, security updates, and expanded documentation.

Changes

CHANGELOG v0.2.0 Release

Layer / File(s)	Summary
Feature additions and behavioral updates CHANGELOG.md	Added section documents new Reddit tracker, collector semantics with TrackerResult validation and hooks, protocol DTO utilities, stable adapters, and error classification. Changed section captures Discord/Slack ingestion updates, typed protocol fields, mailing-list decoupling, concurrency refactor, Celery scheduling, and cross-app import cleanup.
Breaking changes, fixes, and security CHANGELOG.md	Removed section deprecates CollectorBase/DjangoCommandCollector in favor of updated contract classes. Fixed section documents Slack queue race resolution via per-team advisory locking. Security section adds pip-audit CI and lockfile dependency bumps.
Documentation expansion CHANGELOG.md	Documentation section adds collector tutorial, architecture overview, ADRs, pandoc installation guidance, and standardized pull request template.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

🐰 A changelog grows with tales so grand,
New features sprouted, changes spanned,
From Reddit trackers to adapters stable,
v0.2.0 readies—now we're able!
With docs aligned and bugs now mended,
This worthy release is nearly tended. 📝✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly describes the primary change: updating CHANGELOG.md with v0.2.0 [Unreleased] notes in preparation for release.
Description check	✅ Passed	The description fully covers all template sections with clear explanations, explicit marking of N/A items, and checkmarks where appropriate.
Linked Issues check	✅ Passed	The PR addresses issue #276 by updating CHANGELOG.md with v0.2.0 [Unreleased] notes covering changes since v0.1.0, grouped by Added/Changed/Fixed/Removed/Security/Documentation sections per Keep a Changelog format.
Out of Scope Changes check	✅ Passed	All changes are narrowly scoped to CHANGELOG.md documentation updates directly required by issue #276; no application code or out-of-scope modifications are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[snowfox1003]

lgtm