[fatihemres]

M-001B: Modernize SteamAPI to .NET 10 (Release Candidate v0.2.0)

STATUS: DRAFT -- AWAITING PRODUCT OWNER MERGE AUTHORIZATION
This pull request delivers the complete M-001B modernization milestone across Phases 2A through 3E. It remains in DRAFT status until explicit Product Owner release authorization is granted.

---

1. Summary of Completed Modernization Phases

• Phase 2A (.NET 10 Target Framework): Upgraded Core, SteamAPI, and SteamAPI.Tests from net6.0 to net10.0. Modernized GitHub Actions workflow to the official .NET 10 SDK (10.0.x).
• Phase 2B (HTTP Infrastructure Modernization): Replaced obsolete synchronous WebClient and ServicePointManager with an asynchronous, pooled HttpClient (SteamService) registered via IHttpClientFactory. Propagated CancellationToken and enforced a strict 30-second upstream timeout with full body read coverage.
• Phase 2C (API Reliability & Error Handling): Enforced formal model validation and standard RFC 9457 ProblemDetails / ValidationProblemDetails for handled client errors (400), upstream errors (502), and timeouts (504).
• Phase 3A (Technical Audit & Security Review): Verified 0 known package vulnerabilities via dotnet list package --vulnerable.
• Phase 3B (Initial Live Smoke Verification): Verified core search suggestion endpoints against live Steam across cultures 1 (tr_TR), 2 (en_US), and 3 (es_ES).
• Phase 3C (Release Hardening & Documentation):
  • Search input strictly capped at 200 UTF-16 code units ([MaxLength(200)]).
  • Outbound automatic redirects disabled (AllowAutoRedirect = false).
  • Response buffering capped at 1 MiB (MaxResponseContentBufferSize = 1,048,576).
  • Typed SteamResponseParseException introduced and mapped to HTTP 502.
  • Authored developer documentation (README.md, docs/API.md, and docs/releases/v0.2.0-rc-notes.md).
• Phase 3D (Final Controlled Live Steam Integration & Audit): Verified release candidate against live Steam across 6 smoke scenarios and 3 validation scenarios. Conducted a complete outgoing request audit (7 verified completed, at most 8 attempted, within 15-request budget).
• Phase 3E (Documentation Harmonization & Release Readiness): Final documentation harmonization, request accounting correction (~46.7% budget remaining under conservative accounting), merge-safe README updates, and PR metadata alignment.

---

2. Remote CI Verification Evidence

• GitHub Actions Run: 38733996618
• Commit: b36de3519cbd5dbc8474b74a85625fbe0b4dd5b0
• Result: 628 / 628 test executions passed (0 failed, 0 skipped)
  • Ubuntu Latest (Debug): 157 passed
  • Ubuntu Latest (Release): 157 passed
  • Windows Latest (Debug): 157 passed
  • Windows Latest (Release): 157 passed
• Test Suite Inventory: 157 deterministic offline tests (49 baseline regression + 80 HTTP/controller integration + 28 security and contract regression tests).

---

3. Breaking Changes Notice

1. Runtime Requirement: Minimum hosting requirement is .NET 10.0 Runtime.
2. Search Input Boundary: Search terms exceeding 200 UTF-16 code units are rejected with HTTP 400 Bad Request.
3. Structured RFC 9457 Payloads: Errors return standard JSON ProblemDetails / ValidationProblemDetails rather than plain strings.
4. Upstream Error Mapping: Handled upstream failures cleanly map to HTTP 502 Bad Gateway (previously unhandled 500s); timeouts return HTTP 504 Gateway Timeout.

---

4. Known Residual Limitations

• HTML Scraping Fragility: If Valve completely overhauls the suggestion DOM structure removing <a class="match"> tags, the endpoint returns [] (empty results).
• Missing Currency Metadata: The price field remains numeric-only without an ISO 4217 currency code.
• No Application-Level Rate Limiting: Outbound calls to Steam are unthrottled; production deployments should sit behind a reverse proxy or API gateway enforcing client rate limits.
• No Production Monitoring: Distributed tracing, OpenTelemetry, and Prometheus metrics are not configured in this milestone.
• Four Legacy CS8618 Warnings: Unresolved in CultureValue.cs (3) and GetSteamGameInfoRequestModel.cs (1); documented as outside the scope of this release.

---

5. Release Governance and Merge Status

• PR State: DRAFT (Awaiting explicit Product Owner authorization before merge).
• Branch: net10_modernization_planning -> master.
• Pending Actions:
  1. Product Owner final review and approval.
  2. Formal PR review approval and squash/merge into master.
  3. Release tag creation (v0.2.0) and publication.